Biomechanical analysis of a novel bone cement bridging screw system combined with percutaneous vertebroplasty for treating Kummell's disease.

Kummell's Disease (KD) was originally proposed by Dr. Hermann Kummell in 1891 as a type of delayed posttraumatic vertebral collapse, which is a clinical phenomenon. The purpose of this experiment is to compare the strength of bone cement and the novel bone cement bridging screw in the treatment of thoracolumbar Kummell disease (KD) with other treatment methods. Thirty sheep spine specimens were selected. T12 to L2 segments were selected, and a KD intravertebral vacuum cleft model was made at the L1 segment. According to the ways of cement filling, the specimens were divided into percutaneous vertebroplasty (PVP), PVP combined with unilateral percutaneous pediculoplasty (PPP), PVP combined with bilateral PPP, unilateral novel bone cement bridging screw system combined with PVP, and bilateral cement bridging screw system combined with PVP groups. There were two experiments: three-dimensional biomechanical strength test and axial compression test. In the three-dimensional biomechanical strength test, we measured the strength of bone cement in specimens under six motion states, including flexion, extension, left bending, right bending, and left and right axial rotations. In the axial compression test, we detected the maximum axial pressure that the bone cement could withstand when it was under pressure until the bone cement was displaced. The unilateral or bilateral novel bone cement bridging screw with PVP groups had the best strength under flexion, extension, left bending, right bending, and had better biomechanical strength, with a significant difference from the other three groups (p < 0.05). There was no significant difference between the unilateral or bilateral novel bone cement bridging screw with PVP groups (p > 0.05). Unilateral and bilateral novel bone cement bridging screw could achieve similar bone cement strength. Compared with the other three groups, the unilateral or bilateral novel bone cement bridging screw with PVP groups are higher 136.35%, 152.43%; 41.93%, 51.58%; 34.37%, 43.50% respectively. The bilateral novel bone cement bridging screw with PVP could bear the largest pressure under vertical force. To conclude, the novel bone cement bridging screw can increase the strength of bone cement and avoid the loosening and displacement of bone cement in the treatment of KD of the thoracolumbar spine.

Magnetic Resonance Imaging Negative Spine Trauma Followed by a Delayed Intravertebral Vacuum Cleft-Kümmell's Disease: A Case Report and Literature Review.

BACKGROUND: Kümmell's disease (KD) is a rare clinical entity characterized by delayed post-traumatic vertebral body collapse, in which an intravertebral vacuum cleft (IVC) is formed. The patient sustained a minor spinal trauma, and their spine X-ray examinations were negative. However, after an asymptomatic period of months, they developed recurrent back pain because of the progressive vertebral collapse of the affected spine. However, no imaging examination could confirm the magnetic resonance imaging (MRI)-negative initial spinal trauma followed by delayed vertebral collapse with IVC. CASE PRESENTATION: We report a case of KD occurring in a 66-year-old postmenopausal patient whose lumbar MRI on sagittal planes were immediately performed following the initial trauma (a ground-level fall) and revealed that the vertebral integrity or connectivity was not interrupted and the marrow signal was even. After an asymptomatic period of 8 months, the back pain reappeared and progressively exacerbated. The wedge-shaped change in the T11 vertebra with an IVC was confirmed by lumbar computed tomography and MRI. Finally, KD was diagnosed following extensive routine hematological and biochemical workups. Percutaneous kyphoplasty was performed to relieve her back pain by restoring her vertebral stability. CONCLUSIONS: We confirmed that the OVF was not the first step in the KD sequence, and the IVC - KD - could from an initial MRI-negative spine trauma.

Is Kummell's Disease a Misdiagnosed and/or an Underreported Complication of Osteoporotic Vertebral Compression Fractures? A Pattern of the Condition and Available Treatment Modalities.

This narrative review provides the outcomes of minimally invasive surgery (MIS) and describes the available conservative treatment options for patients with osteoporotic vertebral compression fractures (OVCFs) that have risk factors for Kummell's disease (KD). It aims to explore the evidence, emphasize the possible therapy complications, and aims to propose the most efficient clinical strategies for maintaining a good overall condition of individuals who may suffer from neurological deficits from a late-diagnosed OVCF complication. The secondary objective is to sum up the diagnostic particularities concerning individuals prone to OVCFs and KD, as the major risk factor for developing these severe conditions remains osteoporosis. Findings of our narrative review are based on the results found in PubMed, Embase, and Google Scholar from the beginning of their inception to December 2020, described independently by two authors. All of the studies included in the review focus on reporting the following treatment methods: conservative methods, vertebroplasty, kyphoplasty, targeted percutaneous vertebroplasty, frontal and side-opening cannula vertebroplasty, SpineJack, bone-feeling mesh container treatment, and the difference in the cement viscosity used (high vs. low) and the approach used (unilateral vs. bilateral). The comparison of randomized control trials (RCTs) as well as prospective and retrospective case series showed a comparable efficacy of kyphoplasty and vertebroplasty, and described cement-augmented screw fixation and the SpineJack system as effective and safe. Although it should be noted that several studies revealed inconsistent results in regards to the efficacy of using back braces and analgesics in patients who had vertebral fractures that were overlooked or not enrolled in any active surveillance program to track the patient's deterioration immediately. Nevertheless there are non-standardized guidelines for treating patients with OVCFs and their complications already established. Using these guidelines, a treatment plan can be planned that takes into consideration the patients' comorbidities and susceptibilities. However, the primary approach remains the management of osteoporosis and that is why prophylaxis and prevention play a crucial role. These measures reduce the risk of disease progression. Unfortunately, in the majority of cases these measures are not taken into account and KD develops.

Restoration of the intravertebral stability in Kümmell's disease following the treatment of severe postmenopausal osteoporosis by 1-34PTH-a retrospective study.

Following the 1-34PTH application for conservative treatment of Kümmell's disease, the intravertebral cleft was filled or bridged by the osseous tissue; the radiological evidence of further collapsing was absent. Pain and the neurological disorder were relieved; bone turnover markers, BMD as well as the health-related quality of life were improved. INTRODUCTION: Kümmell's disease (KD) patients with severe osteoporosis were applied by the 1-34PTH; the fracture union and the increased bone mineral density (BMD) following this treatment were retrospectively reviewed. METHODS: Twenty-one postmenopausal osteoporosis (PMOP) patients with KD received at least 6 months of 1-34PTH treatment. The medical records, including clinical evaluation symptoms, radiological evaluation for bone union and the stability of intravertebral vacuum cleft (IVC), BMD, and laboratory examination for osteoporosis recovery and health-related quality of life (HRQOL), were reviewed. RESULTS: From baseline to month 12, visual analog scale decreased from 8.24 ± 0.54 to 1.71 ± 0.56 (P < 0.001) and the modified Japanese Orthopedic Association scores increased from 6.86 ± 1.77 to 10.43 ± 1.29 (P < 0.001). Sagittal CT demonstrated that the IVC was filled or bridged by the osseous tissue in all patients. Within the vertebra, the IVC area (IVCA) decreased from 4.50 ± 2.50 to 0 mm2 (P = 0.001) and the mineralized bone area (MBA) increased from 170.91 ± 102.23 to 259.56 ± 98.60 mm2 (P < 0.001). The area ratio of IVC to vertebra decreased from 0.97 ± 0.46 to 0% (P < 0.001), and the area ratio of mineral bone to vertebra was increased from 32.85 ± 14.51 to 54.97 ± 14.01% (P < 0.001). The kyphosis angle increment was 3.43 ± 1.80°, and the loss rate of anterior border height was 11.14 ± 4.82%. No differences were found in posterior border height and spinal canal diameter. The PINP, ß-CTx, BMD, and Short Form-36 Health Survey scores markedly increased. CONCLUSIONS: In KD patients with severe PMOP, 1-34PTH treatment could alleviate the clinical evaluation symptoms, facilitate the recovery of the intravertebral stability, ameliorate the BMD, and improve the HRQoL.

Treatment of Kümmell's disease with sequential infusion of bone cement: A retrospective study.

BACKGROUND: Percutaneous vertebroplasty (PVP) is an effective method for the treatment of neurologically intact Kümmell's disease, but bone cement leakage during surgery is a problem that deserves attention. AIM: To reduce bone cement leakage and evaluate the effect of the sequential infusion of bone cement during PVP for the treatment of stage I or II Kümmell's disease. METHODS: Patients with Kümmell's disease treated in our hospital from September 2015 to September 2018 were retrospectively analyzed. Patients meeting the inclusion and exclusion criteria were divided into two groups: Traditional single infusion and sequential infusion (SI). The visual analog scale (VAS) and Oswestry disability index (ODI) were evaluated and compared, and duration of operation, bone cement content and complications were recorded. RESULTS: Forty-five patients were included in this study; there were 24 in the traditional single infusion group and 21 in the SI group. The VAS and ODI were significantly different for both groups when compared pre- and postoperatively, whereas the differences between 1 wk postoperatively and at the final follow-up were not statistically. When the VAS and ODI of the two groups were compared, there were no significant differences at any time point. The leakage rate of bone cement was significantly lower in the SI group (14.3%, 3 of 21) than that in the traditional single infusion group (41.7%, 10 of 24). CONCLUSION: SI in unipedicular PVP is a safe and effective procedure for neurologically intact Kümmell's disease, and this technique could decrease the incidence of bone cement leakage.

Different Performance of Intravertebral Vacuum Clefts in Kümmell's Disease and Relevant Treatment Strategies.

OBJECTIVES: This study aimed to present the different pattern of intravertebral vacuum cleft (IVC) related to high risk of cement complications in minimally invasive treatments for Kümmell's disease (KD) and relevant treatment strategies. METHODS: A retrospective study from January 2016 to January 2018 was conducted at Wuhan Fourth Hospital and comprised 35 patients with Kümmell's disease. There were seven males and 28 females, and the mean age of the patients was 70.4 years. The patterns of IVC in KD were analyzed. These patients were divided into three groups based on the treatment method used. The treatment methods included long-segment fixation (LSF), posterior short-segment fixation (SSF), and percutaneous kyphoplasty (PKP). We retrospectively reviewed outcomes, including the Oswestry Disability Index (ODI), visual analog scale (VAS) score, anterior height of affected vertebrae, kyphotic Cobb angle, and complications. RESULTS: All patients were followed up for 12-38 months. According to their radiographic appearance we could observe two main patterns of clefts. Pattern I, clefts that were found to be near to the endplate and connected with intervertebral space, the endplate was incomplete. Pattern II, IVC traversed to anterior edge of the vertebral body affected. Both were related to high risk of cement complications in minimal invasive treatments for KD. Good results have been achieved in LSF and SSF groups, the VAS, ODI, anterior height of affected vertebrae and kyphotic Cobb angle showed statistically significant differences between pre- and post-operation and between pre- and final follow-up (P < 0.05). In PKP group, although the VSA and ODI showed statistically significant differences between pre- and post-operation and between pre- and final follow-up (P < 0.05), we could observe that the VSA and ODI rebounded a little at the final follow-up. Cement leakage into intervertebral space occurred in four (44.45%) patients of PKP group. CONCLUSIONS: PKP should be chosen carefully if the IVC of the patient presents to be pattern I or II. LSF and SSF are safe and effective, and can achieve satisfactory correction of kyphosis and vertebral height, with pain relief and improvement in patient's daily life, with few complications.

Failed Percutaneous Vertebroplasty Due to Insufficient Correction of Intravertebral Instability in Kummell's Disease: A Case Report.

Kummell's disease, caused by osteonecrosis of the vertebral body, is a cause of vertebral collapse. In Kummell's disease, intravertebral instability from nonunion between the cement and bone after percutaneous vertebroplasty (PVP) can cause persistent severe pain and dysfunction. A 75-year-old woman presented with severe pain in the lower back, both buttocks, groin, and both posterior thighs for a period of 30 days. Lumbar radiographs and magnetic resonance images showed an acute compression fracture of the first lumbar vertebra with an intravertebral cleft filled with fluid. The patient underwent PVP for the L1 compression fracture; however, this failed to provide sufficient pain relief. The patient was re-evaluated with dynamic radiography, and intravertebral instability and bone cement displacement of the L1 vertebra were detected. Repeat PVP was performed. After the procedure, intravertebral instability was restored and her pain completely subsided. PVP is a good treatment choice for symptomatic Kummell's disease. However, there is no consensus on the best technique of injecting bone cement to achieve optimal results. It is important to inject more bone cement than the volume of the intravertebral cleft to prevent instability caused by nonunion in PVP for Kummell's disease. We report a case of failed PVP because of insufficient correction of intravertebral instability in Kummell's, along with a review of the literature.

The therapeutic effect of intravertebral vacuum cleft with osteoporotic vertebral compression fractures: A systematic review and meta-analysis.

BACKGROUND: To date, there has been ongoing debate over whether intravertebral vacuum cleft (IVC) has the effect of therapeutic efficacy in percutaneous vertebral augmentation (PVA) for the treatment of osteoporotic vertebral compression fractures (OVCFs). OBJECTIVE: The aim of this meta-analysis was to calculate a pooled estimate of the IVCs on the effect of therapeutic efficacy of PVA for the treatment of OVCFs. METHODS: A systematic electronic literature search was performed using the following databases: PubMed, Embase and Cochrane Library; the databases were searched from the earliest available records up to June 2016. Pooled risk ratio (RR) or a mean difference (MD) with 95% confidence interval (CI) was calculated using random- or fixed-effects models. The RevMan 5.2 was used to analyze the data. RESULTS: In the immediate postoperative period, pooled results showed that vertebral height and VAS scores of the IVC patients were significantly lower than those of the non-IVC patients. However, pooled results showed there was no significant difference in kyphotic angle and ODI indices between the two groups. At final follow-up period, significant difference was observed in all the radiological and clinical parameters for the IVC patients with compared to the non-IVC patients in our pooled results. Pooled results showed significant difference with respect to the rate of cement leakage between the two groups. CONCLUSION: The IVCs had an important effect of therapeutic efficacy in PVA for the treatment OVCFs. Therefore, we strongly recommend its strict observation and follow-up for the IVCs patients.

[COMPARISON OF EFFECTIVENESS BETWEEN PERCUTANEOUS VERTEBROPLASTY AND PERCUTANEOUS KYPHOPLASTY FOR TREATMENT OF OSTEOPOROTIC VERTEBRAL COMPRESSION FRACTURE WITH INTRAVERTEBRAL VACUUM CLEFT].

OBJECTIVE: To compare the clinical efficacy and safety between percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) in the treatment of osteoporotic vertebral compression fracture (OVCF) with intravertebral vacuum cleft (IVC). METHODS: Between January 2010 and December 2013, 68 patients with single OVCF and IVC were treated, and the clinical data were retrospectively analyzed. Of 68 patients, 48 underwent PVP (PVP group) and 20 underwent PKP (PKP group). There was no significant difference in age, gender, disease duration, fracture level, bone mineral density (BMD), visual analogue scale (VAS), Oswestry disability index (ODI), and preoperative radiological parameters between 2 groups (P>0.05). The intraoperative incidence of cement leakage, cement volume, and operative time were compared between 2 groups; VAS score was used for evaluation of back pain and ODI for evaluation of dysfunction; the incidence of adjacent vertebral fracture was observed within 2 years. The vertebral height and kyphotic angle were measured on X-ray films; the rate of vertebral compression (CR), reduction rate (RR), progressive height loss (PHL), reduction angle (RA), and progressive angle (PA) were calculated. RESULTS: There was no significant difference in cement volume and the incidence of cement leakage between 2 groups (P>0.05). The operative time in PVP group was shorter than that in PKP group, showing significant difference (t=-8.821, P=0.000). The mean follow-up time was 2.4 years (range, 2.0-3.1 years). The VAS scores and ODI were significantly reduced at 1 day, 1 year, and 2 years after operation when compared with preoperative scores (P<0.05), but there was no significant difference between different time points after operation in 2 groups (P>0.05). Adjacent vertebral fracture occurred in 5 cases (10.4%) of PVP group and in 2 cases (10.0%) of PKP group, showing no significant difference (χ2=0.003, P=0.963). BMD was significantly increased at 1 year and 2 years after operation when compared with preoperative BMD (P<0.05), but no significant difference was found between 2 groups (t=0.463, P=0.642; t=0.465, P=0.646). The X-ray films showed that CR and kyphotic angle were significantly restored at immediate after operation in 2 groups (P<0.05); but vertebral height and kyphotic angle gradually aggravated with time, showing significant difference between at immediate and at 1 and 2 years after operation (P<0.05); there was no significant difference in CR and kyphotic angle between 2 groups at each time point (P>0.05). RR, RA, PHL, and PA showed no significant difference between 2 groups (P>0.05). CONCLUSIONS: There is similar clinical and radiological efficacy between PVP and PKP for treatment of OVCF with IVC. Re-collapse could happen after operation, so strict observation and follow-up are needed.

COMPARISON OF EFFECTIVENESS BETWEEN PERCUTANEOUS VERTEBROPLASTY AND PERCUTANEOUS KYPHOPLASTY FOR TREATMENT OF OSTEOPOROTIC VERTEBRAL COMPRESSION FRACTURE WITH INTRAVERTEBRAL VACUUM CLEFT / 中国修复重建外科杂志

OBJECTIVE: To compare the clinical efficacy and safety between percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) in the treatment of osteoporotic vertebral compression fracture (OVCF) with intravertebral vacuum cleft (IVC). METHODS: Between January 2010 and December 2013, 68 patients with single OVCF and IVC were treated, and the clinical data were retrospectively analyzed. Of 68 patients, 48 underwent PVP (PVP group) and 20 underwent PKP (PKP group). There was no significant difference in age, gender, disease duration, fracture level, bone mineral density (BMD), visual analogue scale (VAS), Oswestry disability index (ODI), and preoperative radiological parameters between 2 groups (P>0.05). The intraoperative incidence of cement leakage, cement volume, and operative time were compared between 2 groups; VAS score was used for evaluation of back pain and ODI for evaluation of dysfunction; the incidence of adjacent vertebral fracture was observed within 2 years. The vertebral height and kyphotic angle were measured on X-ray films; the rate of vertebral compression (CR), reduction rate (RR), progressive height loss (PHL), reduction angle (RA), and progressive angle (PA) were calculated. RESULTS: There was no significant difference in cement volume and the incidence of cement leakage between 2 groups (P>0.05). The operative time in PVP group was shorter than that in PKP group, showing significant difference (t=-8.821, P=0.000). The mean follow-up time was 2.4 years (range, 2.0-3.1 years). The VAS scores and ODI were significantly reduced at 1 day, 1 year, and 2 years after operation when compared with preoperative scores (P0.05). Adjacent vertebral fracture occurred in 5 cases (10.4%) of PVP group and in 2 cases (10.0%) of PKP group, showing no significant difference (χ2=0.003, P=0.963). BMD was significantly increased at 1 year and 2 years after operation when compared with preoperative BMD (P0.05). RR, RA, PHL, and PA showed no significant difference between 2 groups (P>0.05). CONCLUSIONS: There is similar clinical and radiological efficacy between PVP and PKP for treatment of OVCF with IVC. Re-collapse could happen after operation, so strict observation and follow-up are needed.

Intravertebral clefts in osteoporotic compression fractures of the spine: incidence, characteristics, and therapeutic efficacy.

OBJECTIVE: To determine the pathogenesis and characteristics and to assess the long-term effectiveness of polymethylmethacry late (PMMA) vertebroplasty treatment in patients with intravertebral cleft (IVC) in osteoporotic compression fractures. METHODS: A retrospective analysis of radiological and clinical parameters was performed on 388 patients who underwent percutaneous vertebroplasty or kyphoplasty to treat osteoporotic compression fractures from January 2010 to October 2012. IVC sign was observed in the MRI of 47 patients. Postoperative follow-ups were conducted for at least 2 years after surgery. RESULTS: IVC incidence was associated with older age and lower bone mineral density. Other baseline measurements, such as preoperative visual analogue scale and Oswestry Disability Index (ODI), showed no significant difference between IVC and non-IVC fracture patients. Vertebral height and kyphotic angle were corrected after percutaneous vertebroplasty or kyphoplasty with no significant difference in outcome between the two procedures. Restored vertebral height collapsed and the kyphotic angle became aggravated during the 2 years following surgery in patients with IVC. Similarly, initial improvements in visual analogue scale and ODI decreased over time. Non-IVC patients' had a slight recurrence of compression and kyphosis that began to normalize after 1 year. Visual analogue scale and ODI at 2 years' post-surgery was also significantly lower in non-IVC than IVC patients. CONCLUSION: Polymethylmethacrylate vertebroplasty treatment of osteoporotic compression fractures is initially effective for patients with signs of IVC, but compression and kyphosis gradually reoccur. Therefore, we strongly recommend strict observation and follow-up after vertebroplasty.

Kümmell's Disease: Clarifying the Mechanisms and Patients' Inclusion Criteria.

The three major causes of vertebral body collapse include infection, malignant neoplasia, and trauma and it may be difficult to distinguish between them, particularly in the presence of severe osteoporosis. In 1891, however, Dr Hermann Kümmell, further added another possibility of vertebral body crush; the delayed posttraumatic collapse. As originally described, this rare clinical entity includes patients, who after a trivial trauma and an asymptomatic clinical course they develop a progressive vertebral body collapse and a painful kyphosis. Although more than a century has passed from its initial description, only few cases have been reported in the literature, whereas the main pathologic eliciting event is still under investigation. As a consequence, great controversy exists regarding the discrete features of the clinical course, its radiographic appearance and the histopathological findings. To explain the time lag between the initial trauma and the occurrence of the vertebral collapse, the hypothesis of ischemic necrosis was advanced. Equation of Kümmell's disease with vertebral osteonecrosis, however, has wrongly led many authors to report cases of Kümmell's disease, even in the absence of history of spinal trauma. On the other hand, high coincidence of vertebral osteonecrosis and the pathognomonic radiographic finding of intravertebral vacuum cleft, has further added to the confusion. In this review we present an overview of the literature on Kümmell's disease, focusing on the different proposed eliciting mechanisms. We also highlight controversial subjects on clinical course, diagnosis and treatment of this entity, in an attempt to further clarify patients' inclusion criteria.

Vertebral compression fracture with intravertebral vacuum cleft sign: pathogenesis, image, and surgical intervention.

The intravertebral vacuum cleft (IVC) sign in vertebral compression fracture patients has obtained much attention. The pathogenesis, image character and efficacy of surgical intervention were disputed. Many pathogenesis theories were proposed, and its image characters are distinct from malignancy and infection. Percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) have been the main therapeutic methods for these patients in recent years. Avascular necrosis theory is the most supported; PVP could relieve back pain, restore vertebral body height and correct the kyphotic angulation (KA), and is recommended for these patients. PKP seems to be more effective for the correction of KA and lower cement leakage. The Kümmell's disease with IVC sign reported by modern authors was incomplete consistent with syndrome reported by Dr. Hermann Kümmell.

Vertebral Compression Fracture with Intravertebral Vacuum Cleft Sign: Pathogenesis, Image, and Surgical Intervention

The intravertebral vacuum cleft (IVC) sign in vertebral compression fracture patients has obtained much attention. The pathogenesis, image character and efficacy of surgical intervention were disputed. Many pathogenesis theories were proposed, and its image characters are distinct from malignancy and infection. Percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty (PKP) have been the main therapeutic methods for these patients in recent years. Avascular necrosis theory is the most supported; PVP could relieve back pain, restore vertebral body height and correct the kyphotic angulation (KA), and is recommended for these patients. PKP seems to be more effective for the correction of KA and lower cement leakage. The Kummell's disease with IVC sign reported by modern authors was incomplete consistent with syndrome reported by Dr. Hermann Kummell.