Vertebro-/Kyphoplasty History, Development, Results

Many investigations prove the significant analgetic effect of vertebral augmentation. The reasons for the decrease in pain are found in the stabilization of fracture fragments as well as the toxic-thermic effect of polymethylmethacrylate (PMMA), used in the majority of cases. The techniques, primarily in use since 1984, can be divided in vertebro- and kyphoplasty. Vertebroplasty is the direct injection of PMMA into the trabecular vertebral body, while kyphoplasty uses an inflatable bone tamp to create a cavity which is filled with highly viscous cement allowing a certain degree of vertebral height restoration. Both techniques are used percutaneously. Indications for augmentation are painful osteoporotic vertebral fractures, metastatic osteolyses, and painful or destabilizing vertebral hemangiomas. In this article, an overview of the techniques and the history of their development is provided. The materials used for augmentation, the possibilities, limits, and complications of the techniques are discusse

An immunohistochemical study of the tissue bridging adult spondylolytic defects—the presence and significance of fibrocartilaginous entheses

Introduction Spondylolytic spondylolisthesis is an osseous discontinuity of the vertebral arch that predominantly affects the fifth lumbar vertebra. Biomechanical factors are closely related to the condition. An immunohistochemical investigation of lysis-zone tissue obtained from patients with isthmic spondylolisthesis was performed to determine the molecular composition of the lysis-zone tissue and enable interpretation of the mechanical demands to which the tissue is subject. Methods: During surgery, the tissue filling the spondylytic defects was removed from 13 patients. Twelve spondylolistheses were at the L5/S1 level with slippage being less than Meyerding grade II. Samples were methanol fixed, decalcified and cryosectioned. Sections were labelled with a panel of monoclonal antibodies directed against collagens, glycosaminoglycans and proteoglycans. Results: The lysis-zone tissue had an ordered collagenous structure with distinct fibrocartilaginous entheses at both ends. Typically, these had zones of calcified and uncalcified fibrocartilage labelling strongly for type II collagen and aggrecan. Labelling was also detected around bony spurs that extended from the enthesis into the lysis-zone. The entheses also labelled for types I, III and VI collagens, chondroitin four and six sulfate, keratan and dermatan sulfate, link protein, versican and tenascin. Conclusions: Although the gap filled by the lysis tissue is a pathological feature, the tissue itself has hallmarks of a normal ligament—i.e. fibrocartilaginous entheses at either end of an ordered collagenous fibre structure. The fibrocartilage is believed to dissipate stress concentration at the hard/soft tissue boundary. The widespread occurrence of molecules typical of cartilage in the attachment of the lysis tissue, suggests that compressive and shear forces are present to which the enthesis is adapted, in addition to the expected tensile forces across the spondylolysis. Such a combination of tensile, shear and compressive forces must operate whenever there is any opening or closing of the spondylolytic ga

Transcostovertebral kyphoplasty of the mid and high thoracic spine

While Kyphoplasty is increasingly becoming a recognised minimally invasive treatment option for osteoporotic vertebral fractures and neoplastic vertebral collapse, the experience in the treatment of vertebrae of the mid (T5-8)- and high (T1-4) thoracic levels is limited. The slender pedicle morphology restricts the transpedicular approach at these levels, necessitating extrapedicular placement techniques. Fifty five vertebrae of 32 consecutive patients were treated with kyphoplasty at levels ranging from T2-T8 for vertebral fractures (27 patients) or osteolytic collapse (5 patients). All procedures were performed through the transcostovertebral approach under fluoroscopic guidance. The radioanatomical landmarks of this minimally invasive approach were consistently identified and strictly adhered to. One fracture required open instrumentation due to posterior column injury in addition to kyphoplasty. Identification of specific radioanatomical landmarks allowed precise tool introduction in all cases without intraspinal or paravertebral malplacement. Average operating time for patients with osteoporotic fractures was 30min per level (range 13-60min) and 52min per level (range 35-95min) in neoplastic cases. Biopsy yield in patients with known or suspected malignancies was 100%. Epidural cement leakage was detected in one patient with pedicular osteolysis. Perforation of the lateral vertebral cortex during balloon inflation occurred in another patient. Both intraoperative complications were without clinical significance. Kyphoplasty in mid- to -high thoracic levels is possible via the transcostovertebral route under fluoroscopic guidance. Strict adherence to a stepwise protocol of tool introduction following defined radioanatomical landmarks is mandatory for the safe completion of this minimally invasive techniqu

Athletic population with spondylolysis: review of outcomes following surgical repair or conservative management

Objective The study aims to critically review the outcomes associated with the surgical repair or conservative management of spondylolysis in athletes. Methods The English literature listed in MEDLINE/PubMed was reviewed to identify related articles using the term “spondylolysis AND athlete.” The criteria for studies to be included were management of spondylolysis in athletes, English text, and no year, follow-up, or study design restrictions. The references of the retrieved articles were also evaluated. The primary outcome was time to return to sport. This search yielded 180 citations, and 25 publications were included in the review. Results Treatment methods were dichotomized as operative and nonoperative. In the nonoperative group, 390 athletes were included. A combination of bracing with physical therapy and restriction of activities was used. Conservative measures allowed athletes to return to sport in 3.7 months (weighted mean). One hundred seventy-four patients were treated surgically. The most common technique was Buck's, using a compression screw (91/174). All authors reported satisfactory outcomes. Time to return to play was 7.9 months (weighted mean). There were insufficient studies with suitably homogenous subgroups to conduct a meta-analysis. Conclusion There is no gold standard approach for the management of spondylolysis in the athletic population. The existing literature suggests initial therapy should be a course of conservative management with thoracolumbosacral orthosis brace, physiotherapy, and activity modification. If conservative management fails, surgical intervention should be considered. Two-sided clinical studies are needed to determine an optimal pathway for the management of athletes with spondylolysis

Fluoroscopic radiation exposure of the kyphoplasty patient

Kyphoplasty (KP) is a minimally invasive technique for the percutaneous stabilisation of vertebral fractures. As such, this technique is highly dependent upon intraoperative fluoroscopic visualisation. In order to assess the range of radiation doses that patients are typically subjected to, 60 consecutive procedures using simultaneous bilateral fluoroscopy were analysed with respect to exposure time (ET). In a subset of 16 of these patients, a theoretical entrance skin dose (ESD) and effective dose was additionally calculated from intraoperatively measured dose area product. Average fluoroscopy time for single level cases reached 2.2min (range 0.6-4.3) in the lateral plane and 1.6min (range 0.5-3.0) in the anterior-posterior plane. For multiple level cases the corresponding ET per level was 1.7min (range 0.6-2.9) per level in the lateral and 1.1min (range 0.5-2.0) in the anterior-posterior plane. ESD was estimated as an average 0.32Gy (range 0.05-0.86) in the anterior-posterior and 0.68Gy (range 0.10-1.43) in the lateral plane. Effective dose (cumulative from both planes) averaged 4.28mSv (range 0.47-10.14). Safety margins for the development of early transient erythema are respected within the presented fluoroscopy times. Longer ET in the lateral plane may however breach the 2Gy threshold. Use of large c-arms and judiciously operating the exposure is recommended. With regard to effective dose, a single fluoroscopy guided KP performed for osteoporotic or traumatic vertebral fractures is a safe procedur

Development of a new assessment tool for cervical myelopathy using a Virtual Reality hand tracking sensor

Introduction: Myelopathy hand is a characteristic feature of cervical myelopathy. Since there are only a few scales to quantify the severity of cervical compressive myelopathy, there is a need to introduce a universal objective platform in outpatient settings. Virtual-Reality offers promise as a means of producing quantitative data regarding the function of the neural system in the hand. The Leap Motion Controller (LMC) is a small, USB Virtual-Reality motion tracking device that could be used for this purpose. The aim of this study was to assess the reliability and validity of the LMC in the 15-second hand grip-and- release (G-R) test, as compared against human inspection of an external digital camera recording. Moreover, to set a baseline measurement of the number of hand flexion-extension cycles and analyse the degree of motion in young healthy individuals, besides examining gender and dominant hand differences. Materials and Methods: Fifty healthy participants were asked to fully grip-and-release their dominant hand as rapidly as possible for three tests, each separated by a 10-minute rest, while wearing a non-metal wrist splint. The first two tests lasted for 15 seconds, and a digital camera was used to film the anterolateral side of the hand on the first test. The third test lasted for a maximum of three minutes or until subjects fatigued. Three assessors counted the frequency of G-R cycles, of the recorded videos, independently and in a blinded fashion. One assessor counted the frequency of grip-and-release cycles as well as the number of motions (magnitude of motion) from the data output of the LMC. The average mean frequency of the three video observers was compared with that measured by LMC using the Bland-Altman method. Test-retest reliability was examined by comparing the two 15-second tests. Results: The mean number of G-R cycles recorded in each 15-second test was: 47.8 + 6.4 (test 1, video observer); 47.7 + 6.5 (test 1, LMC); and 50.2 + 6.5 (test 2, LMC). Bland Altman indicated a bias of 0.15 cycles (95%CI 1⁄4 0.10-0.20), with upper and lower limits of agreemen

Cement volume is the most important modifiable predictor for pain relief in BKP: results from SWISSspine, a nationwide registry

Purpose: The effectiveness of vertebral augmentation techniques is a currently highly debated issue. The biomechanical literature suggests that cement filling volumes may play an important role in the "dosage” of vertebral augmentation and its pain alleviating effect. Good clinical data about filling volumes are scarce and most patient series are small. Therefore, we investigated the predictors of pain alleviation after balloon kyphoplasty in the nationwide SWISSspine registry where cement volumes are also recorded. Methods: All single-level vertebral fractures with no additional fracture stabilization and availability of at least one follow-up within 6months after surgery were included. The following potential predictors were assessed in a multivariate logistic regression model with the group's average pain alleviation of 41 points on VAS as the desired outcome: patient age, patient sex, diagnosis, preoperative pain, level of fracture, type of fracture, age of fracture, segmental kyphotic deformity, cement volume, vertebral body filling volume, and cement extrusions. Results: There were 194 female and 82 males with an average age of 70.4 and 65.3years, respectively. Female patients were about twice as likely for achieving the average pain relief compared to males (p=0.04). The preoperative pain level was the strongest predictor in that the likelihood for achieving an at least 41-point pain relief increased by about 8% with each additional point of preoperative pain (p4.5ml seem to be recommendable for achieving relevant pain alleviation. Patient sex and fracture type and location were further significant predictors and all these covariates should be recorded and reported in future studies about the pain alleviating effectiveness of vertebral augmentation procedure

Finite element investigation of the effect of spina bifida on loading of the vertebral isthmus

Background: Spondylolysis (SL) of the lower lumbar spine is frequently associated with spina bifida occulta (SBO). There has not been any study that has demonstrated biomechanical or genetic predispositions to explain the coexistence of these two pathologies. In axial rotation, the intact vertebral arch allows torsional load to be shared between the facet joints. In SBO, the load cannot be shared across the arch, theoretically increasing the mechanical demand of the vertebral isthmus during combined axial loading and rotation when compared to the normal state. Purpose: To test the hypothesis that fatigue failure limits will be exceeded in the case of a bifid arch, but not in the intact case, when the segment is subjected to complex loading corresponding to normal sporting activities. Study Design: Descriptive Laboratory Study. Methods: Finite element models of natural and SBO (L4-S1) including ligaments were loaded axially to 1kN and were combined with axial rotation of 3°. Bilateral stresses, alternating stresses and shear fatigue failure on intact and SBO L5 isthmus were assessed and compared. Results: Under 1kN axial load, the von Mises stresses observed in SBO and in the intact cases were very similar (differences <5MPa) having a maximum at the ventral end of the isthmus that decreases monotonically to the dorsal end. However, under 1kN axial load and rotation, the maximum von Mises stresses observed in the ipsilateral L5 isthmus in the SBO case (31MPa) was much higher than the intact case (24.2MPa) indicating a lack of load sharing across the vertebral arch in SBO. When assessing the equivalent alternating shear stress amplitude, this was found to be 22.6 MPa for the SBO case and 13.6 MPa for the intact case. From this it is estimated that shear fatigue failure will occur in less than 70,000 cycles, under repetitive axial load & rotation conditions in the SBO case, while for the intact case, fatigue failure will occur only over 10 million cycles. Conclusion: SBO predisposes spondylolysis by generating increased stresses across the inferior isthmus of the inferior articular process, specifically in combined axial rotation and anteroposterior shear. Clinical Relevance: Athletes with SBO who participate in sports that require repetitive lumbar rotation, hyperextension and/or axial loading are at a higher risk of developing spondylolysis compared to athletes with an intact spine

Prospective analysis of health-related quality of life after surgery for spinal metastases

Purpose Most spinal metastases are detected late and thus the impact of treatment on the health related quality of life (HRQOL) is an important consideration. This study investigated the HRQOL following surgery for spinal metastases. Methods Prospective study of patients operated for symptomatic spinal metastases, at a single tertiary referral spine centre (2011-2013). Data was collected pre-operatively and up to 2 years following surgery (if alive). The HRQOL assessment was performed using recognised systems including the Frankel Score (neurological status), EQ-5D and the Oswestry Disability Index. Results 199 patients were studied (median age 65yrs, 43% (86) F; 57% (113) M). The Frankel score improved significantly after surgery in 69 patients (35%), worsened in 17 (8%), with 20/39 patients regaining the ability to walk (51%). All the HRQOL scores improved significantly following surgery. The complication rate was 27%; median survival 270 days, and 44 patients (22%) survived at 2 years. Conclusions This large prospective study showed that surgical treatment for spinal metastases significantly improved the HRQOL

Development of a new assessment tool for cervical myelopathy using hand-tracking sensor: Part 2: normative values

Purpose To set a baseline measurement of the number of hand flexion–extension cycles and analyse the degree of motion in young healthy individuals, measured by leap motion controller (LMC), besides describing gender and dominant hand differences. Methods Fifty healthy participants were asked to fully grip-and-release their dominant hand as rapidly as possible for a maximum of 3 min or until subjects fatigued, while wearing a non-metal wrist splint. Participants also performed a 15-s grip-and-release test. An assessor blindly counted the frequency of grip-and-release cycles and magnitude of motion from the LMC data. Results The mean number of the 15-s G–R cycles recorded by LMC was: 47.7 ± 6.5 (test 1, LMC); and 50.2 ± 6.5 (test 2, LMC). In the 3-min test, the total number of hand flexion–extension cycles and the degree of motion decreased as the person fatigued. However, the decline in frequency preceded that of motion’s magnitude. The mean frequency of cycles per 10-s interval decreased from 35.4 to 26.6 over the 3 min. Participants reached fatigue from 59.38 s; 43 participants were able to complete the 3-min test. Conclusions Normative values of the frequency of cycles and extent of motion for young healthy individuals, aged 18–35 years, are provided. Future work is needed to establish values in a wider age range and in a clinical setting