Osteoporotic vertebral body fractures of the thoracolumbar spine: indications and techniques of a 360°-stabilization

Satisfactory 2-year outcome of minimal invasive hybrid stabilization with double treated screws for unstable osteoporotic spinal fractures

PURPOSE

This study evaluates whether the fracture level alters the outcomes of minimally invasive hybrid stabilization (MIHS) with double-threaded, uncemented polyaxial screws for unstable osteoporotic vertebral fractures.

METHODS

This prospective cohort study included 73 patients (71.23% females, mean age: 79.9 ± 8.8 years) with unstable OF 3-4 fractures treated by MIHS between Nov 2015-Jan 2018. Patient characteristics, operative data, clinical outcomes, complications, radiological outcomes, and midterm (24-month) follow-up regarding functionality, pain, and quality of life were analyzed.

RESULTS

Patients had thoracolumbar (71.23%), thoracic (10.97%), and lumbar (17.8%) fractures. Operative time was < 120 min in 73.97% of patients, with blood loss < 500 ml in 97.25% of cases. No in-hospital mortality was recorded. Spine-associated complications occurred in 15.07% of patients, while 36.98% of patients had urinary tract infections (n = 12), pneumonia (n = 5), and electrolyte disturbances (n = 9). The mean length of hospital stay was 13.38 ± 7.20 days. Clinically-relevant screw loosening occurred in 1.7% of screws, and secondary adjacent fractures were diagnosed in 5.48% of patients. The alpha-angle improved significantly postoperatively (mean change: 5.4°) and remained stable for 24 months. The beta-angle improved significantly from 16.3° ± 7.5 to 10.8° ± 5.6 postoperatively but increased slightly to 14.1° ± 6.2 at midterm follow-up. Although no differences were seen regarding baseline data, clinical outcomes, and complications, fracture level significantly altered the COMI score at 24 months with no effect on pain score or quality-of-life.

CONCLUSION

MIHS using polyaxial screws is a safe treatment for single-level osteoporotic spinal fractures. Fracture level did not alter radiological reduction loss; however, it significantly altered patients' function at 24 months.

Primary Stability of Kyphoplasty in Incomplete Vertebral Body Burst Fractures in Osteoporosis: A Biomechanical Investigation

Background: The objective of our study was to biomechanically evaluate the use of kyphoplasty to stabilize post-traumatic segmental instability in incomplete burst fractures of the vertebrae. Methods: The study was performed on 14 osteoporotic spine postmortem samples (Th11-L3). First, acquisition of the native multisegmental kinematics in our robot-based spine tester with three-dimensional motion analysis was set as a baseline for each sample. Then, an incomplete burst fracture was generated in the vertebral body L1 with renewed kinematic testing. After subsequent kyphoplasty was performed on the fractured vertebral body, primary stability was examined again. Results: Initially, a significant increase in the range of motion after incomplete burst fracture generation in all three directions of motion (extension-flexion, lateral tilt, axial rotation) was detected as proof of post-traumatic instability. There were no significant changes to the native state in the adjacent segments. Radiologically, a significant loss of height in the fractured vertebral body was also shown. Traumatic instability was significantly reduced by kyphoplasty. However, native kinematics were not restored. Conclusions: Although post-traumatic segmental instability was significantly reduced by kyphoplasty in our in vitro model, native kinematics could not be reconstructed, and significant instability remained.

A New Minimally Invasive Technique for Thoracolumbar/Lumbar Focal Kyphosis Due to Osteoporotic Vertebral Fracture: A Case Report

Osteoporotic vertebral fractures are common fractures in the elderly population and are often associated with low back pain and disruption in daily living activities. Reconstruction surgeries, such as corpectomy, are among the treatment options for these conditions. However, a corpectomy requires a longer surgical procedure and involves a significant amount of blood loss. We present the case of an 80-year-old woman with severe low back pain due to an L2 fracture and focal kyphosis treated with a novel minimally invasive technique. The patient underwent anterior and posterior surgery in the right decubitus position using a C-arm-free technique. Hyperlordotic cages were inserted in the upper and lower disc space via a lateral approach, while percutaneous pedicle screws were inserted from a posterior approach. These procedures were performed simultaneously under navigation guidance only.

Percutaneous kyphoplasty combined with pediculoplasty for the surgical treatment of osteoporotic thoracolumbar burst fractures

OBJECTIVE

This study introduces a minimally invasive technique for efficient three-column reconstruction, augmentation, and stabilization of osteoporotic thoracolumbar burst fractures (OTLBFs).

METHODS

Sixty-eight patients with OTLBFs and no neurological deficits were included from July 2019 to September 2020. The patients were divided into two groups: the simple percutaneous kyphoplasty (PKP) group (n = 32) and the percutaneous kyphoplasty combined with pediculoplasty (PKCPP) group (n = 36). The clinical and radiological outcomes were assessed during a minimum 1-year follow-up period. Clinical outcomes were assessed via the visual analog scale (VAS) and modified MacNab grading criteria. The radiological outcomes included the Cobb angle (CA), anterior wall height (AWH), and posterior wall height (PWH). The surgery duration, postoperative analgesic dosage, length of hospital stay, and complications were recorded.

RESULTS

Surgery duration was not significantly different between the two groups (P > 0.05). The PKCPP group had a lower analgesic dosage and shorter hospital stay (P < 0.05). Postoperatively, the PKCPP group exhibited better VAS scores and modified MacNab scale scores (P < 0.05), but the differences at the last follow-up assessment were not significant (P > 0.05). Postoperative CA, AWH, and PWH correction were not significantly different on the first postoperative day (P > 0.05). However, the PKCPP group had significantly less CA and PWH loss of correction at the last follow-up visit (P < 0.05). The PKCPP group had significantly fewer complications (P < 0.05).

CONCLUSIONS

The PKCPP technique complements simple PKP for OTLBFs. It quickly relieves pain, maintains the vertebral body height and Cobb angle, ensures cement stabilization, and offers more stable three-column support.

Geriatric spine fractures - Demography, changing trends, challenges and special considerations: A narrative review

The aim of this manuscript was to summarize the demography and changing trends of geriatric spinal injuries and to enumerate the challenges and special considerations in the care of geriatric spinal injuries. PubMed, Scopus and Embase databases were searched for literature on geriatric spine fractures using MeSH terms 'aged', 'aged, 80 and over', 'elderly', 'spinal fracture/epidemiology', spinal fracture/therapy∗' and keywords pertaining to the same. The search results were screened for appropriate articles and reviewed. There is a high community prevalence of elderly vertebral fractures ranging from 18% to as high as 51%. The proportion of older patients among the spinal injured is rising as well. There is a higher chance of missing spinal injuries in the elderly and clinical guidelines may not be applicable to this patient group. Classification and surgical treatment are different from younger adult counterparts as the elderly osteoporotic spine behaves differently biomechanically. There is a high incidence of respiratory complications both for surgically and conservatively managed groups. Older age generally is associated with a higher complication rate including mortality.

Georg Schmorl prize of the German spine society (DWG) 2022: current treatment for inpatients with osteoporotic thoracolumbar fractures-results of the EOFTT study

AIM

Osteoporotic thoracolumbar fractures are of increasing importance. To identify the optimal treatment strategy this multicentre prospective cohort study was performed.

PURPOSE

Patients suffering from osteoporotic thoracolumbar fractures were included. Excluded were tumour diseases, infections and limb fractures. Age, sex, trauma mechanism, OF classification, OF-score, treatment strategy, pain condition and mobilization were analysed.

METHODS

A total of 518 patients' aged 75 ± 10 (41-97) years were included in 17 centre. A total of 174 patients were treated conservatively, and 344 were treated surgically, of whom 310 (90%) received minimally invasive treatment. An increase in the OF classification was associated with an increase in both the likelihood of surgery and the surgical invasiveness.

RESULTS

Five (3%) complications occurred during conservative treatment, and 46 (13%) occurred in the surgically treated patients. 4 surgical site infections and 2 mechanical failures requested revision surgery. At discharge pain improved significantly from a visual analogue scale score of 7.7 (surgical) and 6.0 (conservative) to a score of 4 in both groups (p < 0.001). Over the course of treatment, mobility improved significantly (p = 0.001), with a significantly stronger (p = 0.007) improvement in the surgically treated patients.

CONCLUSION

Fracture severity according to the OF classification is significantly correlated with higher surgery rates and higher invasiveness of surgery. The most commonly used surgical strategy was minimally invasive short-segmental hybrid stabilization followed by kyphoplasty/vertebroplasty. Despite the worse clinical conditions of the surgically treated patients both conservative and surgical treatment led to an improved pain situation and mobility during the inpatient stay to nearly the same level for both treatments.

Decompression and fusion surgery for osteoporotic vertebral fractures: WFNS Spine Committee Recommendations

INTODUCTION

Osteoporotic vertebral fractures (OVF) are common due to aging populations. Their clinical management remains controversial. Although conservative approaches are sufficient in most cases, there are certain conditions where decompression or fusion surgery are necessary. This manuscript aims to clarify the indications and types of surgeries for OVF.

EVIDENCE ACQUISITION

A Medline and Pubmed search spanning the period between 2010 and 2020 was performed using the keywords "osteoporotic vertebral fractures and decompression surgery" and "osteoporotic vertebral fractures and fusion surgery". In addition, we reviewed up-to-date information on decompression and fusion in osteoporotic vertebral fracture (OVF) to reach an agreement in two consensus meetings of the World Federation of Neurosurgical Societies (WFNS) Spine Committee that was held in January and February 2021. The Delphi method was utilized to improve the validity of the questionnaire.

EVIDENCE SYNTHESIS

A total of 19 studies examining decompression and fusion surgery in OVF were reviewed. Literature supports the statement that decompression and fusion surgery are necessary for progressive neurological deficits after OVF. The Spine Section of the German Society for Orthopedics and Trauma (DGOU) classification revealed that it might help make surgical decisions. We also noted that in patients planning to undergo surgery to correct significant kyphosis after OVF, several techniques, including multilevel fixation, cement augmentation, preservation of sagittal balance, and avoiding termination at the apex of kyphosis are necessary to prevent complications. Additionally, it became clear that there is no consensus to choose the type of open surgery (anterior, posterior, combined, using cement or bone or vertebral body cage, the levels, and kind of instrumentation). The current literature indicated that implant failure in the osteoporotic spine is a common complication, and many techniques have been described to prevent implant failure in the osteoporotic spine. However, the superiority of one method over another is unclear.

CONCLUSIONS

Open surgery for osteoporotic vertebral fractures should be considered if neurologic deficits and significant painful kyphosis. The apparent indications of surgery and most ideal surgical technique for OVF remain unclear in the literature; therefore, the decision must be individualized.

Long-segment fixation VS short-segment fixation combined with kyphoplasty for osteoporotic thoracolumbar burst fracture

Background

To retrospectively compare clinical and radiological results of long-segment fixation (LF) and six-screw short-segment fixation combined with kyphoplasty (SSFK) for osteoporotic thoracolumbar burst fracture (OTBF).

Methods

Forty patients affected by OTBF with mean age of 61.85 years were included in this study. The mean follow-up period was 13.63 months. Twenty-four patients were treated by SSFK, and 16 patients were treated by LF. Clinical outcomes, radiological parameters and complications were assessed and compared.

Results

The mean operative time and blood loss were 89.71 ± 7.62 min and 143.75 ± 42.51 ml for SSFK group, respectively; 111.69 ± 12.25 min (P < 0.01) and 259.38 ± 49.05 ml (P < 0.01) for LF group, respectively. The two groups were similar in terms of preoperative radiological and clinical results. Compared with preoperative values, both groups achieved significant improvement in terms of VAS, ODI, Cobb angle and anterior vertebral body height (AVH) ratio at final follow-up. However, during the follow-up period, significant loss of Cobb angle and AVH ratio were observed for both groups. Five cases (20.83%) of asymptomatic cement leakage were observed in SSFK group. One case of implant failure and two cases of adjacent or non-adjacent vertebral fractures were observed in LF group.

Conclusions

Both SSFK and LF are safe and effective for treatment of OTBF. Comparatively, SSFK is less invasive and can preserve more motion segments, which may be a more valuable surgical option in some elderly patients. A high-quality randomized controlled study is required to confirm our finding in the future.

Dorsal instrumentation with and without vertebral body replacement in patients with thoracolumbar osteoporotic fractures shows comparable outcome measures

PURPOSE

In the surgical treatment of osteoporotic spine fractures, there is no clear recommendation, which treatment is best for the individual patient with vertebra plana and/or neurological deficit requiring instrumentation. The aim of this study was to evaluate clinical and radiological outcomes after dorsal or 360° instrumentation of osteoporotic fractures of the thoracolumbar spine in a cohort of patients representing clinical reality.

METHODS

A total of 116 consecutive patients were operated on between 2008 and 2020. Inclusion criteria were osteoporotic fracture, thoracolumbar location, and dorsal instrumentation. In 79 cases, vertebral body replacement (VBR) was performed additionally. Patient outcomes including complications, EQ-5D at follow-up, and sagittal correction were analyzed.

RESULTS

Medical and surgical complications occurred in 59.5% of patients with 360° instrumentation compared to 64.9% of patients with dorsal instrumentation only (p = 0.684). Dorsal instrumentation plus VBR resulted in a sagittal correction of 9.3 ± 7.4° (0.1-31.6°) compared to 6.0 ± 5.6° (0.2-22.8°) after dorsal instrumentation only, respectively (p = 0.0065). EQ-5D was completed by 79 patients after 4.00 ± 2.88 years (0.1-11.8 years) and was 0.56 ± 0.32 (- 0.21-1.00) for VBR compared to 0.56 ± 0.34 (- 0.08-1.00) without VBR after dorsal instrumentation (p = 0.994).

CONCLUSION

360° instrumentation represents a legitimate surgical technique with no additional morbidity even for the elderly and multimorbid osteoporotic population. Particularly, if sufficient long-term construct stability is in doubt or ventral stenosis is present, there is no need to abstain from additional ventral reinforcement and decompression.

Georg Schmorl Prize of the German Spine Society (DWG) 2020: new biomechanical in vitro test method to determine subsidence risk of vertebral body replacements

PURPOSE

Prevention of implant subsidence in osteoporotic (thoraco)lumbar spines is still a major challenge in spinal surgery. In this study, a new biomechanical in vitro test method was developed to simulate patient activities in order to determine the subsidence risk of vertebral body replacements during physiologic loading conditions.

METHODS

The study included 12 (thoraco)lumbar (T11-L1, L2-L4) human specimens. After dorsal stabilisation and corpectomy, vertebral body replacements (VBR) with (a) round centrally located and (b) lateral end pieces with apophyseal support were implanted, equally distributed regarding segment, sex, mean BMD ((a) 64.2 mgCaHA/cm³, (b) 66.7 mgCaHA/cm³) and age ((a) 78 years, (b) 73.5 years). The specimens were then subjected to everyday activities (climbing stairs, tying shoes, lifting 20 kg) simulated by a custom-made dynamic loading simulator combining corresponding axial loads with flexion-extension and lateral bending movements. They were applied in oscillating waves at 0.5 Hz and raised every 100 cycles phase-shifted to each other by 50 N or 0.25°, respectively. The range of motion (ROM) of the specimens was determined in all three motion planes under pure moments of 3.75 Nm prior to and after implantation as well as subsequently following activities. Simultaneously, subsidence depth was quantified from fluoroscope films. A mixed model (significance level: 0.05) was established to relate subsidence risk to implant geometries and patients' activities.

RESULTS

With this new test method, simulating everyday activities provoked clinically relevant subsidence schemes. Generally, severe everyday activities caused deeper subsidence which resulted in increased ROM. Subsidence of lateral end pieces was remarkably less pronounced which was accompanied by a smaller ROM in flexion-extension and higher motion possibilities in axial rotation (p = 0.05).

CONCLUSION

In this study, a new biomechanical test method was developed that simulates physiologic activities to examine implant subsidence. It appears that the highest risk of subsidence occurs most when lifting heavy weights, and into the ventral part of the caudal vertebra. The results indicate that lateral end pieces may better prevent from implant subsidence because of the additional cortical support. Generally, patients that are treated with a VBR should avoid activities that create high loading on the spine.

Midterm outcome after posterior stabilization of unstable Midthoracic spine fractures in the elderly

Background

The evidence for the treatment of midthoracic fractures in elderly patients is weak. The aim of this study was to evaluate midterm results after posterior stabilization of unstable midthoracic fractures in the elderly.

Methods

Retrospectively, all patients aged ≥65 suffering from an acute unstable midthoracic fracture treated with posterior stabilization were included. Trauma mechanism, ASA score, concomitant injuries, ODI score and radiographic loss of reduction were evaluated. Posterior stabilization strategy was divided into short-segmental stabilization and long-segmental stabilization.

Results

Fifty-nine patients (76.9 ± 6.3 years; 51% female) were included. The fracture was caused by a low-energy trauma mechanism in 22 patients (35.6%). Twenty-one patients died during the follow-up period (35.6%). Remaining patients (n = 38) were followed up after a mean of 60 months. Patients who died were significantly older (p = 0.01) and had significantly higher ASA scores (p = 0.02). Adjacent thoracic cage fractures had no effect on mortality or outcome scores. A total of 12 sequential vertebral fractures occurred (35.3%). The mean ODI at the latest follow up was 31.3 ± 24.7, the mean regional sagittal loss of reduction was 5.1° (± 4.0). Patients treated with long segmental stabilization had a significantly lower rate of sequential vertebral fractures during follow-up (p = 0.03).

Conclusion

Unstable fractures of the midthoracic spine are associated with high rates of thoracic cage injuries. The mortality rate was rather high. The majority of the survivors had minimal to moderate disabilities. Thereby, patients treated with long segmental stabilization had a significantly lower rate of sequential vertebral body fractures during follow-up.

Which anatomic structures are responsible for the reduction loss after hybrid stabilization of osteoporotic fractures of the thoracolumbar spine?

Introduction

Hybrid stabilization is an accepted therapy strategy for unstable osteoporotic thoracolumbar fractures. However, a moderate reduction loss has been reported and it remains unclear which anatomic structure is responsible for the reduction loss.

Methods

This retrospective study was performed at a level I trauma center. Patients aged 61 and older were stabilized using hybrid stabilization after suffering acute and unstable osteoporotic vertebral body fractures at the thoracolumbar spine. Posterior stabilization was done short-segmental and minimal invasive with cement-augmentation of all pedicle screws. The minimum follow-up has been 2 years. The outcome parameters were the reduction loss and the relative loss of height of both intervertebral discs adjacent to the fractured vertebral body, the fractured vertebral body and a reference disc (intervertebral disc superior of the stabilization) between the postoperative and latest lateral radiographs. Additionally, implant positioning and loosening was analyzed.

Results

29 mainly female (72%) patients (73.3 ± 6.0 years) were included. Fractures consisted of 26 incomplete burst fractures and 3 complete burst fractures of the thoracolumbar junction (Th11 – L2: 86%) and the midlumbar spine. The mean follow-up time was 36 months (range: 24–58 months). The mean reduction loss was 7.7° (range: 1–25). The relative loss of heights of both intervertebral discs adjacent to the fractured vertebral body, the reference disc, and the central vertebral body were significant. Thereby, the relative loss of the superior disc height was significant higher compared to the reference disc. Additionally, only the relative loss of central vertebral body height and reduction loss correlated significantly. There were no signs of implant loosening in any patient.

Conclusions

The mean reduction loss was moderate 3 years after hybrid stabilization of unstable osteoporotic vertebral fractures of the thoracolumbar spine. A significant loss of both adjacent disc heights and the central vertebral body was seen, with the highest loss in the superior adjacent disc significantly outranging the reference disc. The superior adjacent intervertebral disc and the central part of the fractured vertebral body seem to be responsible for the majority of reduction loss.

Risk factors of adjacent segmental fractures when percutaneous vertebroplasty is performed for the treatment of osteoporotic thoracolumbar fractures

The study aimed to analyze the radiographic and magnetic resonance imaging (MRI) findings that might predict the risk for adjacent segmental fractures (ASFs) when percutaneous vertebroplasty (PV) is used for the treatment of osteoporotic thoracolumbar fractures (OTFs). A total of 92 OTFs patients who underwent PV between January 2013 and January 2015 were retrospectively reviewed. The visual analog scale (VAS), Oswestry-Disability Index (ODI) and radiolographic measurements were assessed. The VAS and ODI scores improved significantly at the final follow-up (FU) compared with the preoperation scores. Compared with the preoperative values, the fractured body alignment (FBA) significantly improved at the 3-month FU and the final FU, but the adjacent segment alignment (ASA) and thoracolumbar alignment (TLA) did not improve. According to the correlation analysis, the final FU TLA and the final FU ASA were correlated with the preoperative FBA, ASA, and TLA on plain radiography and were highly correlated on MRI. However, the final FU FBA was not correlated with the preoperative FBA, ASA, or TLA on plain radiography or MRI (P > 0.05). The ASFs were correlated with the 3-month FU TLA (r = 0.6044, P = 0.0037) and the final FU TLA (r = 0.5699, P = 0.007) on plain radiography, and the final TLA was more correlated with the preoperative FBA, ASA, and TLA on MRI than on plain radiography. In conclusion, the preoperative ASA and TLA on MRI were risk factors associated with ASFs in OTFs treated with PV.

Hybrid stabilization of unstable osteoporotic thoracolumbar vertebral body fractures: clinical and radiological outcome after a mean of 4 years

PURPOSE

The aim of this study was to evaluate midterm results after hybrid stabilization of unstable osteoporotic fractures of the thoracolumbar junction.

METHODS

This retrospective study was performed at a level I trauma center. A total of 113 patients aged 61 and older were stabilized using hybrid stabilization consisting of short-segmental posterior instrumentation and augmentation of the fractured vertebral body after suffering an unstable osteoporotic vertebral body fracture at the thoracolumbar spine. All patients were treated by hybrid stabilization. The primary outcome parameters were the ODI score and loss of reduction. Secondary radiological outcome parameters were the sagittal alignment parameters.

RESULTS

Seventy-two women and 41 men (74.6 ± 6.8 years) were included. Sixty-nine patients (61%) were re-evaluated after a mean of 48 months. Seventeen patients have died during the follow-up period (15%). A total of five in-patient complications were documented (4.4%). Additionally, 12 patients (17.4%) suffered from further osteoporotic vertebral body fractures affecting vertebral bodies of different levels. The average ODI score at the final follow-up was 29.9 (± 22.0). Thereby, 66.6% of all patients had low to moderate limitations. The average regional sagittal loss of reduction was 7.4% (± 5.6%). Loss of reduction was below 10° in 78% of the patients. There were statistically significant correlations between the loss of reduction and the ODI score, pelvic incidence and latest Cobb angle, and between the ODI scores and the lumbar lordosis.

CONCLUSIONS

The majority of patients had low or moderate limitations and low to moderate reduction loss. Thereby, high loss of reduction correlated directly with inferior outcomes. These slides can be retrieved under Electronic Supplementary Material.

Comparison of combined posterior and anterior spondylodesis versus hybrid stabilization in unstable burst fractures at the thoracolumbar spine in patients between 60 and 70 years of age

INTRODUCTION

Surgical treatment of unstable burst fractures of the thoracolumbar spine in the elderly population is highly variable with combined posterior and anterior stabilization (CPAS) and posterior augmented stabilization with cementation of the vertebral body (hybrid) being two commonly used techniques. The aim of this study was to compare the clinical and radiographic outcomes of CPAS versus hybrid stabilization for the treatment of unstable burst fractures of the thoracolumbar spine in patients aged between 60 and 70 years.

MATERIALS AND METHODS

A retrospective analysis was performed of all thoracolumbar burst fractures treated surgically in a single level I trauma center between June 2013 and February 2015. Two commonly used strategies of surgical stabilization were compared; the first consisted of initial posterior reduction and bisegmental stabilization, followed by additional anterior spondylodesis (CPAS); the second method comprised a hybrid technique with a posterior cement augmented bisegmental minimally invasive stabilization and kyphoplasty of the fractured vertebral body. Patients were evaluated clinically after a minimum follow-up of 18 months. The primary endpoint was the Oswestry Disability Index (ODI) at the latest follow-up. Secondary parameters of interest were length of in-hospital stay (LIHS), duration of surgery (DS), surgical revisions (SR), pain level (P-VAS), satisfaction level and the SF-36 score (PSC, MSC), the bisegmental postoperative Cobb angle, the reduction loss (RL), and all alignment parameters (pelvic tilt, pelvic incidence, sacral slope, lumbar lordosis, C7 plumb line).

RESULTS

A total of 29 patients were included (17 females, 12 males, mean age 65.6 years ± 3.4 years). The following vertebral bodies were fractured: thoracic level (T) 12: n = 6; lumbar (L) 1: n = 14; L 2: n = 6; L 3: n = 3. CPAS was performed in 10 patients (34%), whereas the hybrid was carried out in 19 patients (66%). There were no statistical significant differences between both study groups regarding age, gender, trauma energy, fracture level, and fracture morphology. The latest follow-up was performed after a mean of 27 months (range 18-53 months). The LIHS between the treatment methods was statistically significant (p < 0.01); CPAS-mean 24 days versus hybrid-mean 12 days. DS was also significantly longer in patients treated with CPAS, 254 versus 95 min for the hybrid group (p < 0.01). No SR were necessary in either group. No significant differences were found regarding the clinical and radiological outcomes between the groups. The mean ODI score was 13.6 in the CPAS patients compared to 10.8 in the hybrid patients without significant differences between the groups. The majority of patients had no (80%) or minor (13%) limitations according to the ODI score. The P-VAS was 2.8 in CPAS and 2.9 in the hybrid group. RL was 7.1° in CPAS and 4.2° in the hybrid group.

CONCLUSIONS

CPAS and hybrid stabilization provide safe and promising short- and middle-term results in patients between 60 and 70 years of age. The majority of patients demonstrated no disability or minimal limitations with either technique. CPAS resulted in prolonged inpatient hospital stays, longer duration of surgery compared to hybrid stabilization without significant differences in clinical and radiological outcome.

Anterior cement augmentation of adjacent levels after vertebral body replacement leads to superior stability of the corpectomy cage under cyclic loading-a biomechanical investigation

BACKGROUND

In the operative treatment of osteoporotic vertebral body fractures, a dorsal stabilization in combination with a corpectomy of the fractured vertebral body might be necessary with respect to the fracture morphology, whereby the osteoporotic bone quality may possibly increase the risk of implant failure. To achieve better stability, it is recommended to use cement-augmented screws for dorsal instrumentation. Besides careful end plate preparation, cement augmentation of the adjacent end plates has also been reported to lead to less reduction loss.

PURPOSE

The aim of the study was to evaluate biomechanically under cyclic loading whether an additional cement augmentation of the adjacent end plates leads to improved stability of the inserted cage.

STUDY DESIGN/SETTING

Methodical cadaver study.

MATERIALS AND METHODS

Fourteen fresh frozen human thoracic spines with proven osteoporosis were used (T2-T7). After removal of the soft tissues, the spine was embedded in Technovit (Kulzer, Germany). Subsequently, a corpectomy of T5 was performed, leaving the dorsal ligamentary structures intact. After randomization with respect to bone quality, two groups were generated: Dorsal instrumentation (cemented pedicle screws, Medtronic, Minneapolis, MN, USA)+cage implantation (CAPRI Corpectomy Cage, K2M, Leesburg, VA, USA) without additional cementation of the adjacent endplates (Group A) and dorsal instrumentation+cage implantation with additional cement augmentation of the adjacent end plates (Group B). The subsequent axial and cyclic loading was performed at a frequency of 1 Hz, starting at 400 N and increasing the load within 200 N after every 500 cycles up to a maximum of 2,200 N. Load failure was determined when the cages sintered macroscopically into the end plates (implant failure) or when the maximum load was reached.

RESULTS

One specimen in Group B could not be clamped appropriately into the test bench for axial loading because of a pronounced scoliotic misalignment and had to be excluded. The mean strength for implant failure was 1,000 N±258.2 N in Group A (no cement augmentation of the adjacent end plates, n=7); on average, 1,622.1±637.6 cycles were achieved. In Group B (cement augmentation of the adjacent end plates, n=6), the mean force at the end of loading was 1,766.7 N±320.4 N; an average of 3,572±920.6 cycles was achieved. Three specimens reached a load of 2,000 N. The differences between the two groups were significant (p=.006 and p=.0047) regarding load failure and number of cycles.

CONCLUSIONS

Additional cement augmentation of the adjacent end plates during implantation of a vertebral body replacement in osteoporotic bone resulted in a significant increased stability of the cage in the axial cyclic loading test.