Elias Panagiotopoulos

Atlas-Based Segmentation of Degenerated Lumbar Intervertebral Discs From MR Images of the Spine

Intervertebral disc degeneration is an age-associated condition related to chronic back pain, while its consequences are responsible for over 90% of spine surgical procedures. In clinical practice, MRI is the modality of reference for diagnosing disc degeneration. In this study, we worked toward 2-D semiautomatic segmentation of both normal and degenerated lumbar intervertebral discs from T2-weighted midsagittal MR images of the spine. This task is challenged by partial volume effects and overlapping gray-level values between neighboring tissue classes. To overcome these problems three variations of atlas-based segmentation using a probabilistic atlas of the intervertebral disc were developed and their accuracies were quantitatively evaluated against manually segmented data. The best overall performance, when considering the tradeoff between segmentation accuracy and time efficiency, was accomplished by the atlas-robust-fuzzy c-means approach, which combines prior anatomical knowledge by means of a rigidly registered probabilistic disc atlas with fuzzy clustering techniques incorporating smoothness constraints. The dice similarity indexes of this method were 91.6% for normal and 87.2% for degenerated discs. Research in progress utilizes the proposed approach as part of a computer-aided diagnosis system for quantification and characterization of disc degeneration severity. Moreover, this approach could be exploited in computer-assisted spine surgery.

Double-Loop Suture Repair for Acute Acromioclavicular Joint Disruption

Background Although it has been established that surgical treatment for acromioclavicular joint disruption (types IV-VI and type III in overhead throwing athletes and heavy laborers) is preferred, the literature is inconclusive about the best type of surgery. Purpose With the goal of avoiding the potential complications of hardware use, the authors present a coracoclavicular functional stabilization technique with the intention to restore the anteroposterior and superior displacement of the clavicle. Study Design Case series; Level of evidence, 4. Methods From 1999 to 2003, 38 patients with an acute, complete acromioclavicular joint separation (34 men, 4 women; mean age, 33.5 years) underwent surgical reconstruction with the described coracoclavicular loop stabilization technique. With this technique, the superior and anteroposterior displacement of the clavicle can be easily controlled using 2 pairs of Ethibond No. 5 nonabsorbable sutures—one passed in front and the other behind the clavicle, through a central drill hole, 2 cm from its lateral end, directly above the base of the coracoid process (at the corresponded attachment of coracoclavicular ligaments). Passive shoulder motion was encouraged by the second postoperative day. Results Thirty-four patients were available for the last clinical and radiologic evaluation. At a mean follow-up of 33.2 months (range, 18-59 months), the mean Constant-Murley score was 93.5 points (range, 73-100 points), and 2 cases with slight loss of reduction (less than half of the width of the clavicle) were detected. Complications included 1 case with superficial infection and 1 patient (basketball player) with persistent tenderness in the acromioclavicular joint without signs of secondary arthritis. The incidence of periarticular ossification was 17.6% and did not affect the final outcome. Secondary degenerative changes were not detected. Conclusion Considering the nearly anatomical reconstruction, the avoidance of hardware complications, and the low rate of recurrence, this technique may be an attractive alternative to the management of acute acromioclavicular joint separations.

Midterm results of treatment with a retrograde nail for supracondylar periprosthetic fractures of the femur following total knee arthroplasty

Objectives: Although the short-term results of supracondylar periprosthetic fractures treated with retrograde nailing have been satisfactory, there is always a concern about the long-term survival of the prosthesis. The aim of the study was to evaluate fracture healing and knee functional outcome with a follow-up time of at least 2 years in periprosthetic fractures of the knee treated with a supracondylar nail. Design: Cohort study. Patients: There were 9 patients with 10 periprosthetic fractures. In 1 patient, the fracture occurred intraoperatively. In the others, the time between the total knee arthroplasty and the periprosthetic fracture ranged between 2 weeks and 7 years (average time: 2.78 years). The mean follow-up was 34.5 months (25-52 months). Main Outcome Measurements: The Western Ontario and McMaster Universities index was used to evaluate the functional result postoperatively using the paired t test as the statistical test. Fracture union was assessed with plain x-rays. Results: All the fractures united within 3 months. One fracture united in extreme valgus (35°) and was revised to a stemmed total knee replacement. There were no infections and no prosthesis loosening. The paired t test before the fracture and after the operation demonstrated no statistically significant differences; however, there was a trend toward lower functional score postoperatively. Conclusions: It appears that retrograde nailing is a reliable technique to treat periprosthetic supracondylar fractures. It provides adequate stability until fracture union. The morbidity of the operation is minimal, and the complication rate is low. The midterm results in our study showed that none of the prostheses required revision. In our opinion, it is the treatment of choice for a periprosthetic fracture when the prosthesis is stable.

The use of the Ilizarov method as a salvage procedure in infected nonunion of the distal femur with bone loss

We reviewed 13 patients with infected nonunion of the distal femur and bone loss, who had been treated by radical surgical debridement and the application of an Ilizarov external fixator. All had severely restricted movement of the knee and a mean of 3.1 previous operations. The mean length of the bony defect was 8.3 cm and no patient was able to bear weight. The mean external fixation time was 309.8 days. According to Paleys grading system, eight patients had an excellent clinical and radiological result and seven excellent and good functional results. Bony union, the ability to bear weight fully, and resolution of the infection were achieved in all the patients. The external fixation time was increased when the definitive treatment started six months or more after the initial trauma, the patient had been subjected to more than four previous operations and the initial operation had been open reduction and internal fixation.

The adult spinal cord injury without radiographic abnormalities syndrome: magnetic resonance imaging and clinical findings in adults with spinal cord injuries having normal radiographs and computed tomography studies.

BACKGROUND Spinal cord injury without radiographic abnormalities (SCIWORA) is thought to represent mostly a pediatric entity and its incidence in adults is rather underreported. Some authors have also proposed the term spinal cord injury without radiologic evidence of trauma, as more precisely describing the condition of adult SCIWORA in the setting of cervical spondylosis. The purpose of the present study was to evaluate adult patients with cervical spine injuries and radiological-clinical examination discrepancy, and to discuss their characteristics and current management. METHODS During a 16-year period, 166 patients with a cervical spine injury were admitted in our institution (Level I trauma center). Upper cervical spine injuries (occiput to C2, 54 patients) were treated mainly by a Halo vest, whereas lower cervical spine injuries (C3-T1, 112 patients) were treated surgically either with an anterior, or posterior procedure, or both. RESULTS Seven of these 166 patients (4.2%) had a radiologic-clinical mismatch, i.e., they presented with frank spinal cord injury with no signs of trauma, and were included in the study. Magnetic resonance imaging was available for 6 of 7 patients, showing intramedullary signal changes in 5 of 6 patients with varying degrees of compression from the disc and/or the ligamentum flavum, whereas the remaining patient had only traumatic herniation of the intervertebral disc and ligamentum flavum bulging. Follow-up period was 6.4 years on average (1-10 years). CONCLUSION This retrospective chart review provides information on adult patients with cervical spinal cord injuries whose radiographs and computed tomography studies were normal. It furthers reinforces the pathologic background of SCIWORA in an adult population, when evaluated by magnetic resonance imaging. Particularly for patients with cervical spondylosis, special attention should be paid with regard to vascular compromise by predisposing factors such as smoking or vascular disease, since they probably contribute in the development of SCIWORA.

Sexual function in females with severe cervical spinal cord injuries: a controlled study with the Female Sexual Function Index.

The objective of this study was to identify the sexual adjustment of females with severe cervical spinal cord injuries (SCI) using the Female Sexual Function Index (FSFI). The 19-item questionnaire of the FSFI concerns sexual function and satisfaction in sex life. This study, conducted by the Orthopaedic and Psychiatry Departments of Patras University, used a sample of a series of 39 consecutive female patients with severe traumatic SCI. We compared these female patients with an age–economic–educational level- and marital status-matched control group of the general population. Sexual activity was lower among females with SCI, but the desire, the emotional quality of sex life and overall sexual satisfaction did not differ from the controls. These results demonstrate that sexual life in females with SCI remains almost unaffected.

Osteoarthritis severity of the hip by computer-aided grading of radiographic images

A computer-aided classification system was developed for the assessment of the severity of hip osteoarthritis (OA) . Sixty-four radiographic images of normal and osteoarthritic hips were digitized and enhanced. Employing the Kellgren and Lawrence scale, the hips were grouped by three experienced orthopaedists into three OA-severity categories: Normal, Mild/Moderate and Severe. Utilizing custom-developed software, 64 ROIs corresponding to the radiographic Hip Joint Spaces were manually segmented and novel textural features were generated. These features were used in the design of a two-level classification scheme for characterizing hips as normal or osteoarthritic (1st level) and as of Mild/Moderate or Severe OA (2nd level). At each classification level, an ensemble of three classifiers was implemented. The proposed classification scheme discriminated correctly all normal hips from osteoarthritic hips (100% accuracy), while the discrimination accuracy between Mild/Moderate and Severe osteoarthritic hips was 95.7%. The proposed system could be used as a diagnosis decision-supporting tool.

Intramedullary nailing in the treatment of aseptic tibial nonunion

Fifty patients suffering from aseptic tibial nonunion underwent reamed intramedullary nailing (I.N.) and were retrospectively reviewed. Thirty-six patients were initially treated with external fixation, six with plate and screws, one with a static I.N., and seven with plaster of Paris. Eighteen of the fractures were initially open (A: 5, B: 6, and C: 7 according to the Gustilo classification). In 34 cases a closed procedure was performed, whereas in sixteen, an opening at the nonunion site was unavoidable either to remove metalwork or realign the fragments. Following failed external fixation, secondary I.N. was performed at least 10 days after removal of the device. Bone grafts from the iliac crest were used in three cases, and a fibular osteotomy was performed in 33. Patients were followed up for an average of 2.5 years after nailing, ranging from 10 months to 7 years. A solid union was achieved in all patients within a period of 6 months. One patient developed late infection, which settled after nail removal and one patient developed impending compartment syndrome which was detected on the first post-operative day and was treated with a fasciotomy. Transient peroneal nerve palsy occurred in one patient and this recovered in 3 months, whereas in nine patients a clinically acceptable deformity was noticed. In conclusion, we believe that reamed intramedullary nailing is a highly effective treatment for aseptic tibial nonunions. Early and late complications are rare and bone graft is rarely needed. The method allows early weight bearing even before solid union occurs, short hospitalisation time and early return to work without external support.

Intramedullary nailing for the treatment of aseptic femoral shaft non-unions after plating failure: Effectiveness and timing

This retrospective, multicentre study aimed to evaluate reamed intramedullary nailing (IMN) for the treatment of 30 cases of aseptic femoral shaft non-union after plating failure. Following nailing, 29 non-unions had healed by a mean 7.93 months. In one case a hypertrophic non-union required renailing after 8 months, using a nail of greater diameter, and united within five further months. Healing times were not related to whether the fracture was open or closed, the type non-union or the type of fracture. The delay from the initial plating to intramedullary nailing had a statistically significant effect on healing time and final outcome. This treatment is cost effective and should be implemented as soon as the non-union is diagnosed.

Delayed diagnosis of a false aneurysm after lumbar arterial injury: treatment with endovascular embolization: a case report.

Study Design. A case report is presented. Objectives. To report a case of lumbar artery pseudoaneurysm that was primarily missed, and to discuss therapeutic options. Summary of Background Data. In the literature, only a few cases of lumbar artery pseudoaneurysms have been reported. The diagnosis is difficult and often delayed, with a sometimes fatal outcome. The treatment is either surgery or endovascular embolization. Methods. In a patient who survived after a fall from 20 feet (6 m) height, a relatively small retroperitoneal hematoma detected during urgent splenectomy was underestimated. Two weeks later, the underlying laceration of the lumbar artery led to the formation of a pseudoaneurysm, which then ruptured causing a large retroperitoneal hematoma and gradual complete femoral nerve palsy. Results. Complete occlusion of the pseudoaneurysm and progressive regression of the retroperitoneal hematoma were achieved by two stages of endovascular embolization. The size of the hematoma was diminished gradually during a period of 12 months, whereas the femoral nerve has completely recovered. Conclusions. Traumatic rupture of a lumbar artery is a rare complication of a blunt abdominal trauma. This condition leads to a potentially massive retroperitoneal hemorrhage and shock, or to subsequent pseudoaneurysm formation and delayed retroperitoneal hematoma. This condition can be managed with either surgical or preferably endovascular intervention provided the patient is hemodynamically stable.