Yoram Anekstein

Platelet Gel (agf) Fails to Increase Fusion Rates in Instrumented Posterolateral Fusions

Study Design. Retrospective cohort study. Objective. To determine the effect on fusion of adding platelet gel to autologous iliac crest graft. Summary of Background Data. Platelet gel is an osteoinductive material prepared by ultra-concentration of platelets and contains multiple growth factors. Proprietary commercial methods are available for harvesting autologous platelet gel concentrates for use as graft supplement in spine fusions. Methods. We reviewed 76 consecutive patients who underwent instrumented posterolateral lumbar fusion with autologous iliac crest bone graft mixed with autologous growth factor (AGF). A control group was randomly selected from patients who underwent instrumented posterolateral lumbar fusion with autologous bone graft alone. The groups were matched for age, sex, smoking history, and number of levels fused. Demographic, surgical, and clinical data were collected from medical records. Diagnosis of nonunion was based on exploration during revision surgery or evidence of nonunion on computerized tomography. The Fisher exact test was used to compare fusion rates. Results. In both groups, mean age was 50 years, and 24% were smokers. The nonunion rate was 25% in the AGF group and 17% in the control group. This difference was not statistically significant (P = 0.18). Conclusions. Platelet gel preparation requires blood draws from the patient. This procedure adds to the risk and cost of surgery. The technique for AGF harvest evaluated in this study provides the highest concentration of platelets among the commercially available methods. Despite this, we showed that platelet gel failed to enhance fusion rate when added to autograft in patients undergoing instrumented posterolateral spinal fusion. The authors do not recommend the use of platelet gel to supplement autologous bone graft during instrumented posterolateral spinal fusion.

Accuracy and safety of thoracic pedicle screw placement in spinal deformities.

Objectives: To determine the safety of pedicle screw fixation in thoracic spine deformity correction. Methods: One hundred twelve pedicle screws were surgically placed in 25 patients with degenerative, posttraumatic, and Scheuermann kyphosis and idiopathic and neuromuscular scoliosis. Screw position was evaluated using intraoperative and postoperative radiographs and thin-slice computed tomography. Results: Of the total 112 thoracic pedicle screws that were inserted, 98 screws (87.5%) were fully contained within the cortical boundaries of the pedicle. When comparing proximal screws (T1-T8) with distal screws (T9-T12) and convex placed screws with concave ones, a statistically significant difference in screw placement was evident (P < 0.05). More misplaced screws were seen proximally and on the concave side. Of the 14 malpositioned screws, 2 (1.8%) demonstrated aortic abutment. There were no neurologic deficits, vascular injuries, or mechanical failures recorded. Conclusions: Placement of thoracic pedicle screws is both feasible and safe.

Intradiscal cement leak following percutaneous vertebroplasty.

Study Design. A retrospective study to detect patients with cement leakage into the disc space following vertebroplasty. Objective. To determine the frequency, causes, and clinical significance of cement leakage into the disc space. Summary of Background Data. Much has been written about cement leakage into the epidural space following vertebroplasty but only little about intradiscal leakage. Methods. A total of 66 patients with 1 cemented osteoporotic, fractured vertebra between T5 and L5 were followed for at least 2 years. Two of the senior authors (Y.M. and A.P.) evaluated independently cement leakage into the disc space, possible causes were investigated, and the clinical results were evaluated according to patient self-assessment. Results. Detected in 27 patients, cement leakage into the disc space did not negatively affect patient satisfaction with the procedure. In 7 of these patients, leakage occurred through an intravertebral vacuum cleft and, in 8, through a perforation of the endplate created by the needle tip. In only 2 patients was cement found to cross the height of the vertebral body and leak into the contralateral disc. Conclusions. Apart from iatrogenic endplate perforation, cement extravasation into the disc space was always found to occur through the fractured endplate or a vacuum cleft. Placing the needle tip far from the fractured endplate and using more solid cement appear to decrease the risk of leakage.

Intermediate screws in short segment pedicular fixation for thoracic and lumbar fractures: a biomechanical study.

To determine the effect of adding pedicle screws at the level of a burst fracture (intermediate screws) on the stiffness of a short segment pedicle fixation, an in vitro biomechanical study was carried out. Six fresh-frozen pig lumbar spine specimens were used. The flexibility of the intact specimens was examined in flexion, extension, lateral bending, and torsion. An unstable burst fracture model was created by the dropped-mass technique. The unstable spine specimens were instrumented with pedicle screws. The flexibility was tested again with and without intermediate screws. The addition of intermediate screws provided a smaller range of motion in flexion-extension (P<0.001), torsion (P<0.001), and lateral bending (P=0.014). The slopes of the load displacement curves increased in flexion (P<0.001), extension (P=0.003), lateral bending (P=0.003), and torsion (P=0.006), signifying a decrease in flexibility. The addition of intermediate screws at the level of a burst fracture significantly increases the stiffness of a short segment pedicular fixation.

Risk factors affecting the immediate postoperative course in pediatric scoliosis surgery.

Study Design. A retrospective analysis of pediatric records of idiopathic scoliosis (IS) and neuromuscular scoliosis (NMS) etiology, in a search for complications and their risk factors immediately following surgical repair. Objective. To evaluate the influence of pre- and intraoperative parameters on the postoperative course and lay the cornerstone for a course-prediction model. Summary of Background Data. Only a few studies have addressed the immediate postoperative complications of pediatric scoliosis surgery. Methods. Our study included all children who underwent spinal fusion for scoliosis in our hospital between 1998 and 2006. The following data were collected: curve etiology, Cobb angle, number of fused vertebrae, fusion approach, and the addition of thoracoplasty. We evaluated the influence of this data on the rate of delayed extubations, length of intensive care unit (ICU) hospitalization, and the presence of major and minor immediate postoperative complications. Results. The study included 126 children (95 IS and 31 NMS). Delayed extubations were recorded in 17 children (3% of IS vs. 45% of NMS). The most common major and minor complications were pulmonary and hematological-biochemical, respectively. Overall pulmonary complications (major and minor) were recorded in 38 children. Major complications (of any category) were recorded in 19 children. Average length of ICU hospitalization was 3.8 days. The rate of complications in the NMS group was significantly higher than in the idiopathic group. Posterior fusions were associated with a significantly lower rate of pulmonary complications and shorter ICU hospitalizations, in comparison to anterior and combined fusions. Cobb angle, number of fused vertebrae, and the addition of thoracoplasty did not correlate with any postoperative parameters. Conclusion. While NMS etiology, anterior and combined fusions correlated with a worse course, the Cobb angle, number of fused vertebrae, and the addition of thoracoplasty did not. Optimization of postoperative care should be carried out accordingly. Scoliosis surgery is safe even in extreme curves and long fusions. Thoracoplasty can be added whenever indicated, in order to improve the overall outcome.

Management of deep wound infection after posterior lumbar interbody fusion with cages.

Objectives To evaluate long-term treatment outcome of patients with infected posterior lumbar interbody fusion (PLIF) managed with surgical debridement and or prolonged antiobiotic treatment without removal of the interbody cages. Methods Between 1996 and 1999, 8 out of 111 patients who underwent PLIF were diagnosed with deep wound infection (7.2%). All infected patients were clinically followed for at least 2 years after completion of the antibiotic treatment. Longer follow-up of at least 6 years duration was performed by a telephone interview. Results Six patients were managed with surgical debridement, wound irrigation, and primary closure of the wound. None of the patients required removal of the instrumentation. In 2 patients, the PLIF cages were repositioned in the face of infection. All 8 patients received 4 to 6 weeks of intravenous antibiotic therapy followed by another 6 to 9 weeks of oral antibiotic administration. At 2-year follow-up, no clinical or laboratory signs of recurrent infection were evident. Four of the 8 patients reported improved clinical status compared with their prefusion status. At 6-year follow-up, 3 patients had minimal disability according to the Oswestry Disability Index and 2 patients had moderate disability with residual leg pain. Conclusions In cases of postoperative deep wound infection after PLIF with cages, removal of the interbody implants is not necessary. Treatment is composed of prolonged antibiotic therapy guided by antimicrobial susceptibility of the isolated bacteria and supplemented with extensive surgical debridement if needed.

Lumbar Stenosis and Systemic Diseases: Is There any Relevance?

Study Design A retrospective study of spinal stenosis patients admitted to Assaf Harofeh Medical Center Orthopedic Departments. Objective To assess any correlation between systemic disease and spinal stenosis. Summary of Background Data Lumbar stenosis is a common spinal disease with various etiologies. No findings have been reported correlating spinal stenosis incidence with background diseases, although diabetes mellitus (DM) has been found to play a role in intervertebral disc degeneration and spondylolisthesis. Methods Hospitalization records of patients with spinal stenosis admitted to Assaf Harofeh Medical Center Orthopedic Departments between 1984 and 1993 were checked for background diseases, age, and sex. The data collected were statistically evaluated for any correlation between spinal stenosis and chronic diseases and compared with the data published by the “Israeli Bureau of Statistics” and Israels largest Health Maintenance Organizations chronic disease survey. Results Of 537 patients with spinal stenosis 57% (308) were males and (229) 43% females with an average age of 60±14 years. Diseases occurring with a high incidence were hypertension (HTN)—23.2% (compared with 7.8% in the general population), DM—13.6% (5.9%), ischemic heart disease (IHD)—11.9%, and hyperlipidemia—4.4%. Patients with spinal stenosis had no significant age and sex distribution difference compared with the general population and no such difference was found for patients suffering from HTN, IHD, or DM. Isolating the effect of DM on HTN and IHD revealed that HTN was a primary disease whereas IHD was secondary to DM with significant statistical validation (P=0.003). Conclusions To the best of our knowledge this is the first study linking spinal stenosis and DM or HTN. It was found that chronic diseases do not alter the natural age and sex distribution of spinal stenosis. The major question remaining concerns the biologic mechanism linking spinal stenosis and DM or HTN.

Aspirin Therapy and Bleeding During Proximal Femoral Fracture Surgery

To assess the effect of daily low-dose aspirin therapy on perioperative bleeding of patients operated on for proximal femoral fracture, we did a prospective case-control study. During 14 months, we followed up 104 patients, 39 of whom were taking aspirin before the injury. The bleeding was estimated by the number of blood units needed perioperatively, the change in hemoglobin values, and followup on complications and drain volume. The aspirin-treated group received an average of 0.5 units of blood more than the control group, postoperatively. This finding was statistically significant. The groups did not differ significantly in any other bleeding parameter. No major bleeding occurred in the patients. It is safe to do surgery for a proximal femoral fracture in patients who are taking aspirin.

Avoiding neurologic complications following ligation of the segmental vessels during anterior instrumentation of the thoracolumbar spine.

Study Design. A retrospective evaluation of anterior instrumentation of the vertebral bodies in the thoracolumbar spine. Objective. To evaluate the possibility of preserving the segmental vessels following anterior instrumentation. Summary of Background Data. Occlusion of the segmental vessels, routinely performed during anterior spine instrumentation, might cause neurologic injury secondary to cord ischemia. Methods. The medical data of 29 patients following anterior instrumentation of the vertebral bodies at the thoracolumbar spine were reviewed. All underwent surgery recently when we decided to preserve the segmental vessels whenever possible. We sought the reasons that enabled us to do so regarding age, gender, underlying pathology, surgical technique, operation duration, instrumentation type and size, and location in the vertebral body. Results. In only 7 patients, fused between T10 and L5, were we able to preserve the segmental vessels. All were instrumented with one 6.25–7-mm wide screw in each vertebral body connected by one rod, approximately half the screws above and half below the segmental vessels. In 22 patients, we were unable to preserve the vessels due to the need to insert 2 screws or a large threaded wide vertebral cage into each vertebra. Conclusions. There is adequate space anteriorly in the vertebral body, above and below the segmental vessels, for the insertion of one screw, even with staples.

Hypothenar hammer syndrome: apropos of six cases and review of the literature.

Hypothenar hammer syndrome (HHS) is a rather rare condition and is a term used to describe an aneurysm or thrombosis of the ulnar artery. It is considered an occupational or recreational injury and is usually a result of a repetitive trauma to the hypothenar region where the unique anatomy of the Guyon canal allows arterial injury. HHS is one of the less common causes of symptomatic ischemia of the upper extremity. The aim of this article is to describe our experience with six patients. Presenting signs, symptoms, differential diagnoses, and literature review of this probably underdiagnosed syndrome are described. There are two pathologic entities: the aneurysmal type and the thrombotic type. Although most authors recommend watchful observation for the thrombotic type, reconstructive surgery is the treatment of choice for the aneurysmal type.