Indomethacin compared with localized irradiation for the prevention of heterotopic ossification following surgical treatment of acetabular fractures

BACKGROUND

There is controversy surrounding the relative effectiveness of local irradiation and oral indomethacin for prophylaxis against heterotopic ossification following surgical treatment of acetabular fractures. The purpose of this study was to compare the efficacy of these two commonly used methods in a prospective, randomized trial.

METHODS

From July 1992 to June 1999, 166 patients in whom a fracture of the acetabulum was treated surgically through a posterior, extensile, or combination approach were randomized to receive either indomethacin or radiation therapy postoperatively. Seventy-eight patients received 800 cGy of local radiation therapy within seventy-two hours after surgery, and seventy-two patients received a six-week course of indomethacin (25 mg three times a day) beginning within twenty-four hours after surgery. Sixteen additional patients were randomized but did not receive treatment with either prophylactic regimen. At an average of fourteen months, the extent of heterotopic ossification was assessed on plain radiographs with use of the classification of Brooker et al. The grade of ossification was correlated with hip motion.

RESULTS

There was no significant difference between treatment groups with regard to patient age, gender, Glasgow Coma Scale, operative time, estimated operative blood loss, duration of follow-up, or presence of closed head injury. The Injury Severity Score appeared to be the only covariate that was significantly different between the groups (p = 0.019). Grade-III or IV ossification developed in eight (11%) of the patients in the indomethacin group and three (4%) in the radiation therapy group. The difference was not significant (p = 0.22; 95% confidence interval, -1.1%, +15.7%). No complications related to the prophylaxis were noted in either group. Heterotopic ossification developed in all sixteen patients who did not receive prophylaxis, with six demonstrating grade-III or IV changes. The overall prevalence of grade-III or IV heterotopic ossification was 7% (eleven of 150) in the treated groups and 38% (six of sixteen) in the untreated group. We did not find any association between the prevalence of heterotopic ossification and fracture type (p = 0.296) or posterior hip dislocation (p = 0.306). Grade-I, II, and III heterotopic ossification did not decrease the range of motion of the hip except in flexion.

CONCLUSIONS

Both local radiation therapy and indomethacin were found to provide effective prophylaxis against heterotopic ossification following surgical treatment of acetabular fractures through a posterior or extensile approach. We detected no significant difference in efficacy between the two prophylactic regimens.

Elution characteristics of tobramycin from polycaprolactone in a rabbit model

This study investigated the elution characteristics of tobramycin from polycaprolactone, a bioabsorbable polymer, in a rabbit model. Sixty rabbits were divided into two groups. Group 1 had polycaprolactone rods impregnated with 6% tobramycin surgically implanted into the proximal femoral intramedullary canal. Group 2 received polymethylmethacrylate rods of like size, shape, and antibiotic concentration. Serum and urine samples were obtained, and tobramycin levels were determined via fluorescent immunosorbent assay. Rabbits were sacrificed as long as 56 days after surgery. Local bone tobramycin concentration was determined using the agar diffusion method. Polycaprolactone delivered a significantly higher peak bone concentration of tobramycin (22.4 microg/mL) than did polymethylmethacrylate (13.59 microg/mL). Polycaprolactone also had a more gradual decrease in local tobramycin concentration than did polymethylmethacrylate. Neither polycaprolactone nor polymethylmethacrylate yielded consistently detectable (> 0.1 microg/mL) serum tobramycin levels. Urine concentrations mirrored those seen in bone, with polycaprolactone achieving significantly higher tobramycin concentrations than did polymethylmethacrylate. Polycaprolactone had superior elution characteristics compared with polymethylmethacrylate in this lapine model, suggesting that polycaprolactone might be a promising local antibiotic delivery vehicle for the treatment of osteomyelitis.

In vitro elution of tobramycin from bioabsorbable polycaprolactone beads

OBJECTIVES

To compare the in vitro elution characteristics of tobramycin impregnated beads made of polycaprolactone (PCL) and polymethylmethacrylate (PMMA).

DESIGN

Six-millimeter PCL and PMMA beads with 6% tobramycin were formed and placed in phosphate-buffered saline or newborn calf serum and incubated at room temperature or 37 degrees C. Aliquots were taken at intervals for eight weeks. Tobramycin levels were determined by fluorescent assay and antibacterial efficacy was assessed by measuring the zones of inhibition against Staphylococcus aureus and Pseudomonas aeruginosa on agar diffusion plates.

RESULTS

Tobramycin elution rates at room temperature were similar up to three weeks. At three weeks, elution rates from PCL beads were twice those from PMMA beads, and at eight weeks, elution from PCL was quadruple that from PMMA. At 37 degrees C, tobramycin elution rates from PCL were eight times greater than those from PMMA by eight weeks. Total tobramycin eluted from PCL beads was 38.9% and 20% in PMMA beads. All samples showed bacteriostatic activity against S. aureus and P. aeruginosa at eight weeks.

CONCLUSIONS

These in vitro results show that PCL has superior antibiotic elution characteristics compared with PMMA, and this may translate into a more effective antibiotic delivery vehicle. In addition, PCL is a bioabsorbable polymer, which may decrease the need for a second surgical procedure to remove retained beads.

Postoperative pain control using epidural catheters after anterior spinal fusion for adolescent scoliosis

STUDY DESIGN

A prospective review of patients undergoing epidural catheter placement after anterior spinal fusion and instrumentation for adolescent scoliosis was performed. Data were collected using visual analog pain scores reflecting the patients' perception of their pain control.

OBJECTIVES

To present the authors' technique for epidural catheter placement and dosing protocol, and to demonstrate the results from postoperative pain control after anterior spinal instrumented fusion for 10 consecutive patients.

SUMMARY OF BACKGROUND DATA

The literature regarding the benefits of epidural catheters after spinal surgery is contradictory, even with controlled studies comparing epidural catheters with intravenous morphine patient-controlled anesthesia. The authors believe that this lack of consensus stems from varied epidural dosing protocols and techniques in catheter placement, which they have witnessed anecdotally at their own institution. This prompted the authors to develop and refine a standardized dosing and catheter placement protocol for pain control after spinal surgery.

METHODS

Epidural catheters were placed intraoperatively before wound closure, then removed on postoperative Day 5. Dosing consisted of fentanyl (1 microg/kg) and hydromorphone (5 microg/kg) diluted in preservative-free saline (0.2 mL/kg). After surgery, dosing consisted of 0.1% ropivacaine and hydromorphone (10 microg/ml) continuously infused at 0.2 mL/kg/hour. Postoperative pain control was assessed on each postoperative day using a visual analog pain scale with choices ranging from 0 to 10.

RESULTS

The arithmetic mean of the median pain scores after surgery was 2.1. The mean of the maximum pain scores for the 5 days was 4.1. Three patients required an epidural bolus and a 20% increase in the epidural infusion rate. One patient was judged to be excessively sleepy, so the epidural infusion rate was decreased by 20%. Pruritus requiring diphenhydramine developed in three patients. No other adverse effects related to epidural analgesia were noted. No catheters were accidentally pulled out or disconnected.

CONCLUSION

By following the dosing protocol described, epidural catheters can be used safely and effectively to control postoperative pain after anterior instrumentation and spinal fusion for adolescent scoliosis.

A dual epidural catheter technique to provide analgesia following posterior spinal fusion for scoliosis in children and adolescents

BACKGROUND

The authors report their experience with the use of a dual epidural catheter technique in controlling pain following long posterior spinal fusion and instrumentation for scoliosis in children and adolescents.

METHODS

Following completion of the surgical procedure and prior to wound closure, the upper catheter was inserted with the tip directed cephalad to T1-4 while the tip of the lower catheter was positioned at the L1-4 level. As the surgical wound was being closed, the catheters were dosed with fentanyl and hydromorphone followed by a continuous infusion of ropivacaine plus hydromorphone. Postoperative pain was assessed every 2-4 h using a visual analogue score or an observational behavioural score (0=no pain, 10=worst imaginable pain). There were 14 patients ranging in age from 5-17 years (12.7 +/- 3.5) and in weight from 19-68 kg (44.3 +/- 17.5). The epidural catheters were left in place until the fifth postoperative day.

RESULTS

The mean of the median pain score from each patient was 1.5 +/- 1.6, 1.6 +/- 1.5, 1.4 +/- 1.3, 1.1 +/- 1.1 and 0.9 +/- 0.9, respectively, on postoperative days 1 through 5. The mean of the maximum pain scores was 3.5 +/- 2.3 (range 0-7), 4 +/- 1.6 (range 2-6), 3.1 +/- 1.7 (range 1-6), 2.4 +/- 1.5 (range 0-4) and 2.2 +/- 1.4 (range 0-4), respectively, on postoperative days 1 through 5.

CONCLUSION

No adverse effects related to epidural analgesia were noted.

Extensor tendon rupture secondary to the AO/ASIF titanium distal radius plate without associated plate failure: a case report

Complications with open reduction and internal fixation of distal radius fractures have led to the development of the AO/titanium Pi-plate. This was designed to be a low-profile plate to decrease its intrusion into surrounding soft tissues. Recent case reports are revealing an association of tendon ruptures with failures of this plate. This case report demonstrates extensor tendon rupture without plate failure or prominent screw heads.

Miliary tuberculosis presenting with rigors and developing unusual cutaneous manifestations

We report a case of miliary tuberculosis presenting with high fevers and rigors. While undergoing evaluation, the patient developed a diffuse, erythematous, maculopapular eruption coalescing to form erythematous plaques involving the abdomen, trunk, and proximal extremities. Biopsies of the lesions were smear- and culture-negative for Mycobacterium tuberculosis. Rigors are an unusual presenting symptom of miliary tuberculosis and have only been reported three times in the (post-antibiotic era) literature. Chills have been reported to occur 28% of the time. This symptom can be confusing to the practitioner, leading to delay in diagnosis. The skin lesions were most consistent with a lichenoid tuberculid eruption. The patient had a negative purified protein derivative and non-reactive anergy panel, and the lesions involved only the cutis and healed without scarring. The patient had a dramatic response to antituberculous therapy, with resolution of the fever within 2 days and resolution of the rash within 2 weeks.

Polycaprolactone/glass bioabsorbable implant in a rabbit humerus fracture model

Research in improved materials and methods for internal fixation has centered on internal fixators made of bioabsorbable materials such as polylactic acid, polyglycolic acid, and polyparadioxanone. These materials have two problems: the first is a postoperative complication related to a delayed inflammatory response; and the second is low strength characteristics. An alternative material developed to alleviate these problems is a composite of phosphate glass fibers embedded in the polymer polycaprolactone, referred to as PCL. In this study, intramedullary pins made of PCL were compared to stainless steel pins in a rabbit humerus osteotomy model. Specimens were harvested at 0, 6, and 12 weeks postoperatively, radiographs and mechanical testing to failure were performed at each time interval, and tissue was examined microscopically at 6 and 12 weeks. Histologic results showed PCL pins to be well tolerated with minimal inflammation around the pin. Mechanical testing revealed the PCL fixation to be weaker initially than the stainless steel fixation. There was significant stress shielding of stainless-steel-healed rabbit humeri when compared to the PCL/bone humeri. All osteotomies immobilized with PCL healed with abundant periosteal callus production.