Expansion Thoracoplasty Affects Lung Growth and Morphology in a Rabbit Model: A Pilot Study

Background  

Thoracic insufficiency syndrome represents a novel form of postnatal restrictive respiratory disease occurring in children with early-onset scoliosis and chest wall anomalies. Expansion thoracoplasty improves lung volumes in children with thoracic insufficiency syndrome; however, how it affects lung development is unknown.     

A New Endovascular Radiofrequency Device for Dilatation of Vascular Stenosis in a Rabbit Model

ABSTRACT

Purpose: To investigate the use of a new endovascular radiofrequency (RF) device, the Habib? VesCoag? Catheter, to induce vascular remodeling and dilatation of arterial stenosis in a rabbit model. Materials and Methods: RF was used to induce arterial stenosis in 10 rabbits and this was confirmed by angiography and color Doppler ultrasound. Two groups of five animals were then subjected to (1) balloon dilatation of the stenosis (intervention group), (2) no intervention (control group). Two rabbits from each group were sacrificed following the procedures to investigate vessel histopathology. At six weeks, the remaining six rabbits underwent follow-up angiogram and color Doppler ultrasound to assess vessel patency. They were then sacrificed and the vessels prepared for histopathological analysis. Three-dimensional images with confocal microscopy of the arterial lumen were also acquired. Results: In the intervention group, stenosis was reversed and patency confirmed by angiography and color Doppler ultrasound six weeks later in all surviving rabbits. Histopathology revealed degenerative changes of elastic fibers, focal losses of elastica lamella, disorganization of myocytes and extensive hyalinization of the tunica adventitia. Focal elastin changes of the arterial elastic lamella were also shown by three-dimensional confocal microscopy images. Conclusion: We have developed a novel endovascular RF catheter that can be safely and effectively used to induce vascular remodeling and dilatation of arterial stenosis in an experimental rabbit model.     

Capacitive Coupling Reduces Instrumentation-related Infection in Rabbit Spines: A Pilot Study

Background  

Postoperative spine infections cause considerable morbidity. Patients are subjected to long-term antibiotic regimens and may require further surgery. Delivery of electric current through instrumentation can detach biofilm, allowing better antibiotic penetration and assisting in eradicating infection.     

Radiofrequency Energy on Cortical Bone and Soft Tissue: A Pilot Study

Background  

Radiofrequency-generating energy devices have been used clinically in musculoskeletal procedures to provide hemostasis and capsular shrinkage (thermal capsulorrhaphy). However, the dose-effects are not well known.     

Interstitial Radiofrequency Therapy of the Prostate: Results of a Pilot Study

Purpose

We assessed the feasibility of using interstitial radiofrequency therapy for benign prostatic hyperplasia (BPH) in 50 patients.

Materials and Methods

Therapy was given using a standard diathermy unit as the radiofrequency generator and a disposable needle electrode. The main outcome measure was improvement in symptoms assessed by symptom scores.

Results

Patients with bothersome symptoms or acute retention showed clinically significant improvements in symptom score, while those with chronic retention did not. There were no serious complications.

Conclusions

Interstitial radiofrequency therapy may be effective for symptomatic BPH. Further studies with long-term objective data are under way to assess its role in the management of BPH.     

Shilla Growing Rods in a Caprine Animal Model: A Pilot Study

There are few good surgical options that allow for continued spinal growth in patients with early-onset scoliosis. The “Shilla” is a growth guidance system that does not require repeated surgical lengthenings. The Shilla system guides growth at the ends of dual rods with the apex of the curve corrected, fused, and fixed to the rods. The growth occurs through the extraperiosteally implanted pedicle screws that slide along the rods at either end of the construct. We implanted 11 2-month-old immature goats with the dual rod system and euthanized all 11 goats 6 months postoperatively. We evaluated plain radiographs, regular computed tomography, microcomputed tomography, physical and histologic examinations, and a microscopic wear analysis. All of the goat spines grew with the implants in place; growth occurred in both the thoracic and lumbar ends of the rods for a total average of 48 mm. None of the implants failed, although we observed minor wear at the rod/screw interface. Growth guidance with the Shilla rod system allowed for continued growth in this goat model.     

Epiphysiodesis: evaluation of a new technique

Proximal tibial epiphyseal fusion was performed in immature black Labrador retriever dogs using an 8-mm drill followed by a high-speed burr. Epiphysiodesis was complete at 2 weeks in all experimental animals (average growth of 1.5 mm, whereas the unoperated side averaged 5.9 mm of growth). Minimal surgical exposure resulted in less pain in the experimental animals than in those undergoing epiphysiodesis by traditional means. This new technique may be of use in pediatric orthopedic patients.     

Percutaneous Radiofrequency Ablation Versus Repeat Hepatectomy for Recurrent Hepatocellular Carcinoma: A Retrospective Study

Background  Whether percutaneous radiofrequency ablation (PRFA) is as effective as repeat hepatectomy for recurrent small hepatocellular carcinoma (HCC) in the long-term remains unknown. Methods  We included 110 patients into this study. Each patient had fewer than three recurrent HCCs, with the largest tumor less than 5 cm in diameter. Sixty-six patients with 88 tumors were treated by PRFA and 44 patients with 55 tumors were treated by repeat hepatectomy. Results  The 1-, 2-, 3-, 4-, and 5-year overall survival rates after repeat hepatectomy and PRFA were 78.6%, 56.8%, 44.5%, 30.7%, and 27.6%, and 76.6%, 48.6%, 48.6%, 39.9%, and 39.9%, respectively (P = 0.79). The 1-, 2-, 3-, 4-, and 5-year overall survival rates after the initial hepatectomy for the two groups were 95.4%, 79.1%, 65.0%, 50.4%, and 42.9%, and 98.5%, 85.0%, 70.8%, 58.7%, and 55.6%, respectively, (P = 0.18). Subgroup analyses showed that there was no significant difference between the overall survivals of the two groups of patients when the interval of tumor recurrence from the initial hepatectomy was ≤1 year (P = 0.74) or >1 year (P = 0.69), and for recurrent tumor ≤3 cm (P = 0.62) or >3 cm (P = 0.57). Major complications happened significantly more often after repeat hepatectomy than PRFA (30 of 44 versus 2 of 66, P < 0.05). The interval of recurrence from the initial hepatectomy, the diameter of the recurrent tumor and the serum albumin level were significant prognostic factors for overall survival. Conclusion  PRFA was as effective as repeat hepatectomy in the treatment of recurrent small HCC. PRFA had the advantage over repeat hepatectomy in being less invasive.     

Acinetobacter baumannii is not Associated with Osteomyelitis in a Rat Model: A Pilot Study

Background  

Multidrug resistant Acinetobacter baumannii (MDR AB) with and without Staphylococcus aureus (SA) is a commonly isolated organism in infected segmental bone defects in combat-related trauma in Iraq and Afghanistan. Although MDR AB in visceral infections is a therapeutic challenge, control of infection appears more common for combat-related osteomyelitis.     

Percutaneous Radiofrequency Ablation versus Partial Hepatectomy for Multicentric Small Hepatocellular Carcinomas: A Nonrandomized Comparative Study

Background  

The aim of this study was to compare the results of percutaneous radiofrequency ablation (RFA) with those of partial hepatectomy (PH) in the treatment of multicentric small hepatocellular carcinomas (HCCs). With advances in RFA, it is not known whether the minimally invasive approach with percutaneous RFA could attain comparable survival outcomes but with a lower morbidity in patients with multicentric HCCs.     

Epiphysiodesis: two-year clinical results using a new technique

A new technique for epiphysiodesis was used to treat seven children with lower limb length discrepancies. A low-speed, high-torque drill was used to ablate the epiphyseal plate through a 1-cm incision under image intensification control. Roentgenographically, the physes appeared to be fused as early as 1 month postoperatively. Clinically, growth was arrested at the time of the operation because the discrepancy never became greater than it was at the time of surgery and improved in all cases at subsequent follow-up visits. No failures of fusion, post-operative infections, restricted joint motion, or angular deformities were encountered.     

Stent-Assisted Percutaneous Endoscopic Necrosectomy for Infected Pancreatic Necrosis: Technical Report and a Pilot Study

World Journal of Surgery - A variety of minimally invasive techniques have been proposed to replace open surgery for the treatment of infected pancreatic necrosis (IPN). In this study, we evaluate...     

Osteoid Osteoma of the Calcaneus: Percutaneous Radiofrequency Ablation

Osteoid osteoma of the foot can pose particular problems in diagnosis, especially when positioned in a juxta-articular location. It can cause reactive synovitis and simulate arthritis without periostitis. An atypical presentation may delay diagnosis and thus delay treatment. Different modes of treatment have been described including medical management with nonsteroidal, antiinflammatory drugs, and open surgical resection with intralesional, marginal, or wide surgical margins. In recent years, several computed tomography-guided percutaneous techniques have been used to achieve ablation of the nidus with minimal tissue invasion. We report a case of a 39-year-old man with an 8-month history of persistent foot pain who underwent percutaneous radiofrequency ablation of an osteoid osteoma involving the calcaneus. The patient related an immediate relief of pain and had no recurrence of symptoms or the lesion at 3-year follow-up.     

Histologic Response to Injected Phosphatidylcholine in Fat Tissue: Experimental Study in a New Rabbit Model

The application of phosphatidylcholine to the fat tissue of humans for aesthetic purposes has recently been in evidence, despite the sparse literature corroboration of this practice. The authors developed a new experimental model to study injection of substances in fat tissue in rabbits. The objective of this particular study was to verify the possible effects of phosphatidylcholine injected in the animals. The animal weight, the fat pad weight, the presence of inflammatory infiltrate, and fibrosis and necrosis at the application sites were observed. Two groups of rabbits received five weekly applications to the dorsal fat pad. The control group received saline solution 0.9%, and the study group received phosphatidylcholine. The removed fat tissue was evaluated 3, 7, 14, and 21 days after the fifth application was completed. The phosphatidylcholine group presented more intense inflammatory infiltrate and fibrosis than the control group (p = 0.05). Necrosis was not observed in any animal. There was no statistically significant difference with regard to the weights of the animal or the fat pad. On the basis of this study, the injection of phosphatidylcholine is relatively safe, but no effect was observed regarding the reduction of fat tissue volume. New studies with higher doses are needed to justify the clinical use of this substance.     

Epiphysiodesis for limb length discrepancy: a comparison of two methods

A retrospective review of 42 patients from 1999 to 2008 with at least 1-year follow-up was performed. The type and location of epiphysiodesis, average operative time and hospital stay, complications, timing and the final limb length discrepancy (LLD) were recorded. Computer tomography scanograms and mechanical axis view with grids were done to assess LLD. Twenty-six patients underwent Canale type epiphysiodesis compared with 14 receiving Metaizeau screw epiphysiodesis. The average operation time for Canale type was 42 and 45 min for screw epiphysiodesis. In the Canale group, there was a mean reduction in 2.5 cm in LLD from 3.7 to 1.2 cm over an average follow-up of 2.1 years. There were 4 minor and 2 major complications with a 92 % success rate defined as achieving the desired discrepancy correction. In the screw epiphysiodesis group, the mean change was 1.8 cm from 3.2 to 1.4 cm, over 2.2 years with 2 minor and 2 major complications and a success rate of 85 %. Percutaneous epiphysiodesis by any method is a reliable, minimally invasive method with minimal morbidity and an acceptable complication rate when compared to a corrective osteotomy or an open Phemister-type epiphysiodesis. This study has led to our preference for the Canale method, which in our hands has fewer complications and is more successful at reaching the desired discrepancy correction.     

Epiphysiodesis in slipped capital femoral epiphysis: a comparison of various surgical modalities

This retrospective study surveys patients treated between 1960 and 1978 for slipped capital femoral epiphyses. The parameters reported are fusion time, blood replacement, hospitalization time, aseptic necrosis, cartilage necrosis, and complications. Twenty-eight hips (24 patients) were treated by pinning, and three hips (three patients) were treated by Smith-Petersen nails. The Heyman or Howorth bone pegging procedures were performed in 48 hips in 41 patients. The average fusion time was 9.4 months for hips treated with Knowles pins, 3.7 months for Hagie or Tachdjian pins, and 4.8 months for bone pegging procedures. Blood loss, hospitalization time, surgical scars, and duration of anesthesia were greater for the bone pegging procedures.     

Learning Curve for Percutaneous Radiofrequency Ablation of Pulmonary Metastases From Colorectal Carcinoma: A Prospective Study of 70 Consecutive Cases

Background Percutaneous radiofrequency ablation (RFA) for inoperable colorectal pulmonary metastases is associated with a morbidity rate of 30% to 40%. A learning curve in this treatment approach has not been documented before.Methods The clinical and treatment-related data regarding 70 consecutive percutaneous RFA procedures for inoperable colorectal pulmonary metastases were collected prospectively. A comparison between the initial 35 cases (group 1) and the subsequent 35 cases (group 2) was performed. Univariate and multivariate analyses were conducted to identify the significant risk factors for overall morbidity, pneumothorax, and chest drain requirement.Results There was no hospital mortality. The overall morbidity rate was 37%. The rate of pneumothorax was 27%. Twelve patients (17%) required chest drain insertion for pneumothorax. There was a significant decline in the incidence of overall morbidity, pneumothorax, and chest drain requirement in group 2 as compared with group 1. Both the number of lung metastases ablated and the RFA treatment period (group 1 vs. group 2) were independent risk factors for overall morbidity, pneumothorax, and chest drain requirement. Distribution of lung metastases (unilateral vs. bilateral) was an independent risk factor for overall morbidity and pneumothorax, but not for chest drain requirement.Conclusions There is a learning curve for percutaneous lung RFA. With accumulated experience in this procedure, a low morbidity rate can be achieved.     

A Porcine Knee Model Is Valid for Use in the Evaluation of Arthroscopic Skills: A Pilot Study

Background

Previously validated knee arthroscopy evaluation tools have used human cadaveric knees. This is unsustainable because of the cost and scarcity of these specimens. Porcine (pig) knees are anatomically similar, affordable, and easily obtainable; however, whether porcine knees represent a suitable alternative to human specimens has not been evaluated.

Questions/purposes

The purpose of this study was to determine whether porcine knees are similar to human cadaveric knees for the assessment of knee arthroscopy skills by evaluating (1) the validity of the porcine model (whether trainees of the same level of ability scored similarly when using the two models) and (2) the reliability of the porcine model (whether surgeons with experience achieved higher scores than surgeons with less experience in the porcine model).

Methods

Eleven orthopaedic surgery residents (five junior residents and six senior residents), one orthopaedic sports medicine fellow, and three attending orthopaedic surgeons were enrolled. Participants were provided instructions for a proper arthroscopic examination of the knee and asked to identify, and then probe, the listed anatomic structures on both the human and porcine knee specimens. Each participant was asked to demonstrate the following skills: joint manipulation, instrument control and triangulation, fluid management, maintenance of field of view, economy of movement, and efficiency. The Objective Assessment of Arthroscopic Skills (OAAS) and checklist for diagnostic arthroscopy of the knee were used for skills assessment by one observer. Internal consistency, a measure of how well the assessment tool measures the skills being studied, was determined by Cronbach’s α and group differences investigated by paired t-test and Wilcoxon signed-rank tests where appropriate. Based on a sample size calculation, a total of 37 subjects would be required for the full-scale research study to achieve a power of 0.80, with α set at 0.05, to detect a difference in OAAS score of 4.73 (25%). This value is outside of the 95% confidence intervals for the human knee.

Results

We found the porcine model to have a high level of face validity. There was no difference with the numbers available in total OAAS scores (mean ± SD; 95% confidence interval [CI]) within subjects between the human (18.93 ± 7.54; 14.76–23.11) and porcine (17.87 ± 6.36; 14.34–21.39) knees (p = 0.433). There was also no difference (p = 0.234) with the numbers available in overall OAAS score among participants working on either human (2.60 ± 1.35; 1.85–3.35) or porcine (2.33 ± 0.90; 1.84–2.83) specimens. Internal consistency of the simulation for both the human and porcine knees was high and did not differ between groups (Cronbach’s α was 0.919 in the human knee and 0.954 in the porcine knee), suggesting the OAAS outcome score specifically assesses arthroscopic skill of participants in both the human and porcine models. More experienced arthroscopists scored higher than did less experienced trainees; there was high correlation (Pearson’s correlation coefficient r, 95% CI) between years of experience and total OAAS scores in human (0.78; 0.46–0.92) and porcine (0.80; 0.49–0.93) diagnostic arthroscopy models.

Conclusions

The porcine cadaveric knee model was a valid surrogate for the human knee in arthroscopic skills assessment.

Clinical Relevance

Trainees can be objectively evaluated using an affordable model that allows summative and formative feedback in the laboratory at a fraction of the cost of previously validated methods.