Influence of implant density and flexibility index on curve correction after scoliosis surgery.

BACKGROUND: Numerous studies proved that all pedicle screw constructs produce the best outcome in the surgical treatment of patients with scoliosis. However, the optimal amount and distribution of screws has not yet been defined. In recent studies on idiopathic scoliosis, the correlation between curve correction and implant density has been discussed with diversifying results. PURPOSE: The aim of this study was to detect a possible correlation of sagittal and coronal curve correction in dependence of metal load and flexibility index. MATERIALS AND METHODS: Twenty-six patients were included in this study with surgical correction by one surgeon between January 2014 and December 2017. Clinical data and radiographic images (preoperative, postoperative and one-year follow-up) were retrospectively analyzed and metal load, flexibility index, correction rate and correction index were consequently calculated. The Pearson correlation analysis was used for metal load-correction index and metal load-correction rate, correction of kyphosis-metal load and correction of lordosis-metal load. According to the mean metal load of 88%, patients were divided into two subgroups-a low-density group of 12 patients and a high-density group of 14 patients. Clinical and radiographic features were examined by an independent two-sided t-test. RESULTS: Eight patients were male, 18 patients female. Ten suffered from neuromuscular and 16 from idiopathic scoliosis. Mean age was 17.1 years. Correction rate directly postoperative was 70.43%, at the follow-up 67.90%. Mean correction index directly postoperative was 3.40 and at the follow-up 3.23. Pearson correlation of metal load-correction index directly postoperative was - 0.188 and one year postoperative - 0.189. The correlation between metal load-correction rate immediately after the surgery was 0.324 and at the follow-up 0.285. Correlation for correction of kyphosis-metal load postoperative was - 0.120 and one year later - 0.178. Pearson coefficient of lordosis-metal load directly after the surgical intervention was - 0.214 and at the follow-up - 0.220. Dependency of flexibility index and correction rate showed a positive trend (Pearson flexibility-correction rate direct 0.616; flexibility index-correction rate follow-up 0.516). A statistically significant difference between the high- and the low-density group was detected in the correction rate directly postoperative (p = 0.047). CONCLUSION: With an implant density over 70%, satisfactory surgical treatment can be achieved in idiopathic and neuromuscular scoliosis. No statistical significance between the high-density (88-100%) and the low-density (73-87%) group could be verified in curve correction, ICU stay and complications.

Treatment strategies for severe C1C2 luxation due to congenital os odontoideum causing tetraplegia.

PURPOSE: High-grade C1C2 luxation is a rare pathology. There is no clear evidence as to how to treat this deformity. There is only limited evidence about the different surgical techniques and possible approaches including advantages, disadvantages, and complications. METHODS: This is an uncommon case of a 13-year-old child with progressive, tetraplegia due to congenital os odontoideum with translational instability between C1 and C2, and progressive luxation of C2. An irreducible dislocation of the C0/C1 complex caused significant compression at the cervicomedullary junction and neurologic deficit. In this paper we highlight the different types of os odontoideum, a review of existing evidence of surgical correction. We will discuss the different treatment strategies which could be applied and the current solution will be described. RESULTS: Continuous skeletal traction and translational reduction was achieved by a specially designed halo traction system including continuous skeletal traction in a wheelchair for 6 weeks. The surgical treatment consisted of a posterior only release, translational reduction and posterior instrumentation from C0 to C4 with a Y plate and homologous bone graft. Neurological deficits started to improve during halo traction. After surgery the patient was ambulatory without any assistance and reached a Frankel stage E. Postoperative X-rays and CT scan revealed complete reduction at the C1/C2 level and a decompressed cervicomedullary junction. CONCLUSION: Treatment of severe C1C2 luxation is difficult with limited evidence in the literature. The current case shows a successful treatment strategy to reduce the deformity and lists alternative approaches.

Severe kyphoscoliosis after primary Echinococcus granulosus infection of the spine.

A primary Echinococcus granulosus infection of the spine involving the vertebrae T8 and T9 of a 6-year-old child was treated elsewhere by thoracotomy, partial corporectomy, multiple laminectomies and uninstrumented fusion. Owing to inappropriate stabilization, severe deformity developed secondary to these surgeries. X-rays, CT and MRI scans of the spine revealed a severe thoracic kyphoscoliosis of more than 100 degrees (Fig. 1) and recurrence of Echinococcus granulosus infection. The intraspinal cyst formation was located between the stretched dural sac and the vertebral bodies of the kyphotic apex causing significant compression of the cord (Figs. 2, 3, 4). A progressive neurologic deficit was reported by the patient. At the time of referral, the patient was wheelchair bound and unable to walk by herself (Frankel Grade C). Standard antiinfectious therapy of Echinococcus granulosus requires a minimum treatment period of 3 months. This should be done before any surgical intervention because in case of a rupture of an active cyst, the delivered lipoprotein antigens of the parasite may cause a potentially lethal anaphylactic shock. Owing to the critical neurological status, we decided to perform surgery without full length preoperative antiinfectious therapy. Surgical treatment consisted in posterior vertebral column resection technique with an extensive bilateral costotransversectomy over three levels, re-decompression with cyst excision around the apex and multilevel corporectomy of the apex of the deformity. Stabilisation and correction of the spinal deformity were done by insertion of a vertebral body replacement cage anteriorly and posterior shortening by compression and by a multisegmental pedicle screw construct. After the surgery, antihelminthic therapy was continued. The patients neurological deficits resolved quickly: 4 weeks after surgery, the patient had Frankel Grade D and was ambulatory without any assistance. After an 18-month follow-up, the patient is free of recurrence of infection and free of neurologically deficits (Frankel E). This case demonstrates that inappropriate treatment--partial resection of the cyst, inappropriate anterior stabilization and posterior multilevel laminectomies without posterior stabilization--may lead to severe progressive kyphoscoliotic deformity and recurrence of infection, both leading to significant neurological injury presenting as a very difficult to treat pathology. Fig. 1 X-rays of the patient showing a kyhoscoliotic deformity. a ap view, b lateral view Fig. 2 CT reconstruction of the whole spine showing the apex of the deformity is located in the area of the previous surgeries Fig. 3 Sagittal CT-cut showing the bone bloc at the apex with a translation deformity Fig. 4 Sagittal T2-weighted MRI image showing the cystic formation at the apex.

Injury of the right and left inferior epigastric artery during the implantation of a stand-alone ALIF cage through a left retroperitoneal approach: a case report.

Various perioperative vascular complications of anterior lumbar spine procedures have been described in orthopaedic literature. We report the unusual case of a perioperative bleeding from the right and left epigastric inferior artery occurring when using a stand-alone ALIF device (Synfix, Synthes, Oberdorf, Switzerland) at the L5/S1 level through an anterior left retroperitoneal approach. The primary stability of the Synfix is achieved by four divergent screws which are inserted through the anteriorly located plate into the neighbouring vertebral endplates. For the screw insertion the surrounding structures have to be mobilized more extensively than during a "standard" anterior lumbar interbody fusion (ALIF) procedure. The epigastric inferior arteries were embolized by applying polyvinyl alcohol particles and metal coils. The retroperitoneal haematoma caused herniation of the external rectus sheath. Hence revision surgery with removal of the haematoma and resuturing of the rectus sheath were performed. Insertion of divergent screws of the Synfix device may cause severe distension and rupture of the epigastric vessels. This case shows that a lesion of the right epigastric artery may be a hazard even in left retroperitoneal approaches. To the author's knowledge this is the first case describing a lesion of the right epigastric artery during an ALIF procedure through a left retroperitoneal approach.

Migration of hip revision stems into the knee joint: alternative treatment modalities: technical note.

We report two unusual cases of stem penetration of long shaft femoral prosthesis into the knee joint after revision total hip arthroplasty. In both patients, the protruded tip of the stem interfered with the tibial plateau and averted the knee joint from full range of motion. To avoid further extensive surgery, the tips of the femoral stem were excised using a high speed-cutter. Both patients had immediate improvement in range of motion postoperatively, fast and uncomplicated rehabilitation, immediate pain relief, and good radiological results. If this rare complication occurs, we recommend for a primary intervention to cut the tip of the stem because replacement of the prosthesis would be a long lasting and very exhaustive surgery for affected patients.

Correlation between objective gait parameters and subjective score measurements before and after total knee arthroplasty.

The absence of uniformity, the use of different terminologies, and the diversity of methods used to translate numerical data into clinical outcomes have been described as potential problems when dealing with clinical knee scores for total knee arthroplasty (TKA). Gait analysis is believed to provide more objective parameters. The aim of the present study was to obtain information about the correlation between the outcome in terms of locomotion and the clinical knee score after TKA. Thirty consecutive patients awaiting TKA were involved in the study. One day prior to surgery and 3 months postoperatively, data pertaining to the Hospital for Special Surgery Score (HSS) and the Knee Society Score (KSS) (subgroups 'pain', 'knee', 'function' and 'total sum') were analyzed for correlations with kinematic and temporospatial parameters of gait analysis. At a significance-level of p

Comparison of conventional versus minimally invasive extraperitoneal approach for anterior lumbar interbody fusion.

The purpose of the study was to compare conventional versus minimally invasive extraperitoneal approach for anterior lumbar interbody fusion (ALIF). Fifty-six consecutive patients with spondylolisthesis, lumbar instability, or failed back syndrome were treated with ALIF between 1991 and 2001. The patients were retrospectively evaluated and divided in two groups: Group 1, consisting 33 patients, was treated with ALIF using the conventional retroperitoneal approach, and Group 2, consisting of 23 patients, was operated with the minimally invasive muscle-splitting approach for ALIF. The groups were comparable as regards age, indication of fusion, and diagnosis. All patients in both groups had fusion with autologous iliac crest grafts and posterior instrumentation with posterolateral fusion in the same sitting. Clinical evaluation was done by two questionnaires: the North American Spine Society (NASS) Lumbar Spine Outcome Assessment Instrument and the Nottingham Health Profile (NHP). Fusion rate was evaluated radiologically. Mean clinical follow-up was 5.5 years. There was no statistical difference in the occurrence of complications with both approaches nor with the fusion rates of 92% in group 1 and 84% in group 2 respectively. The minimally invasive extraperitoneal approach for ALIF was associated with significantly less intraoperative blood loss, operation time, and length of the skin incision. In addition, this approach showed significant improvement in postoperative back pain in comparison to the conventional approach for ALIF.

Infection of a total hip arthroplasty with Prevotella loeschii.

Infection is a serious complication of total hip replacement. It has been proposed that 6% of all infections after total hip arthroplasty may be of dental origin through hematogenous spread. However, no conclusive evidence that the mouth is a definitive source for infection of a total hip replacement has been reported. In the current case, Prevotella loeschii, a pigmented bacteroides species was identified in a total hip replacement. Prevotella loeschii is an organism which exclusively inhabits the dental region. Hematogenous spread of Prevotella loeschii may occur after penetration of the mucosal barrier in cases of endodontic or periodontic lesions, pericoronitis, or complications of tooth extraction. The involvement of Prevotella loescheii in an infection in a patient who had a total hip arthroplasty is strong evidence for the mechanism of a hematogenous infection from a dental source.

Radiographic evaluation of cervical spine trauma. Plain radiography and conventional tomography versus computed tomography.

Different imaging modalities are available for the diagnosis of cervical spine injuries. There is a controversial discussion about whether plain radiography (PR), conventional tomography (CTO) or computed tomography (CT) should primarily be used. PR and CTO are more often available and less costly than CT. Especially in second-care hospitals, CT is not always available. The diagnostic work-up in these centres has to rely on conventional techniques. The aim of this study was to define the role of PR supplemented by CTO in the diagnosis of cervical spine trauma in comparison to CT. Twenty-five patients were identified who underwent plain radiography (PR), conventional tomography (CTO) and computed tomography (CT) for the diagnosis of a cervical fracture. In 19 patients a fracture of the cervical spine was identified. All images were reviewed by two independent observers to estimate the interobserver variability. The highest detection rate was achieved by CT (18/18 fractures detected for observer 1/2), followed by CTO (16/16 fractures) and then PR (15/14 fractures). When the detection rates of PR and CTO are combined, 18 fractures were detected by each of the observers. The results were analysed for the dens and the rest of the cervical spine independently. For PR and CTO the detection rates were lower for fractures of the dens than for the rest of the cervical spine. We conclude that the combination of PR and CTO accurately detects fractures of the cervical spine compared with CT. If a fracture of the dens is suspected, the patients should be referred to CT due to its superior accuracy in this region.

Fistula between a total hip arthroplasty and the rectum: a case report.

An 81-year-old man was referred to the authors for examination of the gastrointestinal tract. A proctoscopy revealed a draining sinus tract in the terminal rectum. Plain radiographs revealed a failed total hip arthroplasty that had migrated into the pelvis. Hip aspiration revealed an infection with bacteria commonly found in the gastrointestinal tract. A fistulogram confirmed a connection between the rectum and the hip replacement. The development of a fistula between the colon and the hip is extremely uncommon. A fistula between the hip and the rectum is a previously unreported complication of total hip arthroplasty.

Multisegmental pneumatocysts of the lumbar spine mimic osteolytic lesions.

Circumscribed radiolucencies within the vertebral bones can be due to a variety of changes including benign and malignant tumours or tumour-like lesions. Radiolucencies due to degenerative intraosseous pneumatocyst are very uncommon but have to be taken into the differential diagnosis in well-circumscribed lytic lesions of the vertebral bodies. We describe the first case of multisegmental pneumatocysts in the lumbar spine mimicking osteolytic lesions. On computed tomography, the air-equivalent attenuation values of the lesions and the close vicinity to the degenerated vertebral endplates with vacuum phenomenon led to the correct diagnosis.

Radiographic assessment in total knee arthroplasty.

Sixty-five total knee arthroplasties were evaluated by the Knee Society Radiological Evaluation System which was developed to encourage uniform reporting of the results of total knee arthroplasty. All patients were examined by three independent experienced radiologists 8.9 years after surgery (range, 3-16 years) to analyze the interobserver variability. For measurement of angles, high interobserver correlation was calculated for the prosthetic component angles and the femorotibial shaft angle. The comparison of the means indicated no significant differences except for the femorotibial shaft angle. For measurement of radiolucent lines, interobserver correlation was low for all components. The differences of the means were significantly different for all components. The results of interobserver variability of the patellar evaluation revealed high interobserver correlation for the patellar angle and for patellar subluxation and dislocation evaluation. For assessment of patellar mediolateral and superoinferior displacement, a low interobserver correlation was found. For radiographic assessment of total knee arthroplasty, the measurement of angles, including alpha, beta, femorotibial shaft angle, sagittal femoral and tibial component angle, patellar angle, and patellar subluxation and dislocation evaluation are recommended. The method of assessing radiolucent lines should be reconsidered.

False aneurysm 14 years after total hip arthroplasty.

Many reports of complications after total hip arthroplasty have been published concerning typical orthopaedic problems. Relatively little attention has been paid to serious vascular injuries, such as the development of a false aneurysm. To our knowledge, 10 cases have been described in the English literature. The mean time interval between surgery and initial manifestation of the aneurysm was 9 months in these cases. Our patient developed first symptoms of a false aneurysm 14 years after surgery. A minimally invasive technique was used to cut the aneurysm from perfusion. Removal of the total hip arthroplasty was performed through a retroperitoneal and lateral approach.

Weight gain in adolescents during pregnancy: rate related to birth-weight outcome.

This study of 459 subjects from prenatal clinics for teenagers at three universities across the United States, addresses questions about gestational weight gain in adolescents raised by the 1990 Institute of Medicine Report. Rate and pattern of gain, independent of pregravid weight, are based on serial measures of mothers with favorable and unfavorable outcomes. Rate of gain (determined by using regression statistics) from weeks 15 to 40 was 0.588, 0.510, and 0.488 kg/wk for mothers of term infants weighing 3000-4000 g, term infants weighing < 3000 g, and preterm infants, respectively. The significantly lower percentage of infants weighing 3000-4000 g vs < 3000 g needing intensive care at birth (6% vs 15%, respectively, P < 0.05) further indicates the superior outcome among mothers with higher rates of gain. Rate of gain of mothers of infants weighing 3000-4000 g (favorable outcome) equaled the highest amount provisionally recommended, suggesting that restricting natural gain of adolescents to recommended rates may result in smaller than optimal infants.