Helical plating - a novel technique to increase stiffness in defect fractures

Single-plate fixation bridging bone defects provokes nonunion and risks plate-fatigue failure due to under- dimensioned implants. Adding a helical plate to bridge the fracture increases stiffness and balances load sharing. This study compares the stiffness and plate surface strain of different constructs in a transverse contact and gap femoral shaft fracture model. Eight groups of six synthetic femora each were formed: intact femora; intact femora with lateral locking plate; contact and gap transverse shaft osteotomies each with lateral locking plate, lateral locking plate and helical locking plate, and long proximal femoral nail. Constructs underwent non-destructive quasi-static axial and torsional loading. Plate surface strain evaluation was performed under 200 N axial loading. Constructs with both lateral and helical plates demonstrated similar axial and torsional stiffness- independent of the contact or gap situations - being significantly higher compared to lateral plating (p < 0.01). Torsional stiffness of the constructs, with both lateral and helical plates in the gap situation, was significantly higher compared to this situation stabilised by a nail (p < 0.01). Plate surface strain dropped from 0.3 % in the gap situation with a lateral plate to < 0.1 % in this situation with both a lateral and a helical plate. Additional helical plating increases axial and torsional construct stiffness in synthetic bone and seems to provide well-balanced load sharing. Its use should be considered in very demanding situations for gap or defect fractures, where single-plate osteosynthesis provides inadequate stiffness for fracture healing and induces nonunion.

Does a polyaxial-locking system confer benefits for osteosynthesis of the distal fibula: A cadaver study

BACKGROUND

In plate osteosynthesis involving the distal fibula, antiglide plating is superior to lateral plating in terms of the biomechanical properties. The goal of this study was to examine whether polyaxial-locking implants confer additional benefits in terms of biomechanical stability.

METHODS

Seven pairs of human cadaveric fibulae were subjected to osteotomy in a standardized manner to simulate an uncomplicated Weber B fracture. The generated fractures were managed with a dorsolateral antiglide plate. To this end, one fibula of the pair was subjected to non-locking plating and the other to polyaxial-locking plating. Biomechanical tests included quantification of the primary bending and torsional stiffness. In addition, the number of cycles to failure in cyclic bending loading were determined and compared. Bone mineral density was measured in all specimens.

RESULTS

Bone mineral density was comparable in both groups. Primary stability was higher in the polyaxial-locking group under torsional loading, and higher in the non-locking group under bending loading. The differences, however, were not statistically significant. All specimens except for one fixed-angle construct failed the cyclic loading test. The number of cycles to failure did not differ significantly between polyaxial-locking and non-locking fixation.

CONCLUSION

In a cadaveric Weber B fracture model, we observed no differences in biomechanical properties between polyaxial-locking and non-locking fixation using an antiglide plate. Based on the biomechanical considerations, no recommendation can be made regarding the choice of the implant. Further biomechanical and clinical studies are required.

CLINICAL RELEVANCE

Information on the behavior of polyaxial-locking plates is relevant to surgeons performing internal fixation of distal fibula fractures.

The influence of the Peroneus Longus muscle on the foot under axial loading: A CT evaluated dynamic cadaveric model study

BACKGROUND

Subtle hypermobility of the first tarsometatarsal joint can occur concomitantly with other pathologies and may be difficult to diagnose. Peroneus Longus muscle might influence stability of this joint. Collapse of the medial longitudinal arch is common in flatfoot deformity and the muscle might also play a role in correcting Meary's angle.

METHODS

A radiolucent frame was used to simulate weightbearing during CT examination. Eight pairs fresh-frozen lower legs were imaged in neutral position under non-weightbearing (75N), weightbearing (700N) and with 15kg weights hung from Peroneus Longus tendon. Measurements included first metatarsal rotation, intermetatarsal angle, first tarsometatarsal joint subluxation and Meary's angle.

FINDINGS

Weightbearing significantly increased Meary's angle and significantly decreased first tarsometatarsal joint subluxation (both P<0.01). Pulling Peroneus Longus tendon significantly increased first metatarsal rotation (P<0.01), significantly decreased the intermetatarsal angle (P<0.01) and increased non-significantly Meary's angle (P=0.52).

INTERPRETATION

A considerable effect weightbearing has on the medial longitudinal arch and first tarsometatarsal joint was observed. Pulling Peroneus Longus tendon improved first metatarsal subluxation but increased its rotation. The study calls into question the importance of this tendon in maintaining the medial longitudinal arch and raises concerns about rotational deformity of the first metatarsal following hallux valgus correction without first tarsometatarsal arthrodesis.

CLINICAL RELEVANCE

Study outcomes will provide more insight in foot pathology.

WHAT IS KNOWN ABOUT THE SUBJECT

Weightbearing affects anatomy of the foot. No reliable information is available concerning the influence of the Peroneus muscle.

WHAT THIS STUDY ADDS TO EXISTING KNOWLEDGE

This study investigates the influence of weightbearing and the impact the Peroneus muscle on the anatomy of the foot.

The Impact of High Protein Nutritional Support on Clinical Outcomes and Treatment Costs of Patients with Colorectal Cancer

BACKGROUND

The primary objective of this study was to investigate the impact of high protein oral nutrition support (ONS) on clinical outcomes in patients with colorectal cancer (CRC). The secondary aim was to compare the cost of treatment and length of stay (LoS) for CRC patients taking high protein ONS vs. patients on conventional nutritional support.

MATERIALS AND METHODS

The study was conducted on adult patients with CRC undergoing colorectal surgery. Informed consent was obtained before the study. The study group (SG; n = 52) was instructed to take high protein ONS (600 kcal, 40 g protein per day) in addition to a normal diet for at least 10 days before and two weeks after surgery. Data from the comparative group (CG; n = 105) were collected retrospectively.

RESULTS

A relative reduction in the frequency of the following complications was observed in SG: wound dehiscence (2.2 times lower), infections (4.3 times lower), anastomosis dehiscence (2.0 times lower), and rehospitalization (1.7 times lower). The mean LoS was shorter in SG (9.4 ± 4.97 vs. CG 12 ± 6.4 days), which resulted in significantly lower treatment costs during hospitalization (SG 479 vs. CG 538 EUR; p = 0.01) and at six months after surgery (SG 4,862 vs. CG 6,456 EUR).

CONCLUSION

Pre- and postoperative high protein ONS reduces LoS, treatment costs, postoperative complications, and re-hospitalizations in CRC, regardless of initial nutritional status.Key words: high protein oral nutritional support - colorectal cancer - perioperative care.

[Fluorescence angiography in the detection of anastomotic perfusion during rectal and sigmoid resection - preliminary report]

INTRODUCTION

The aim of the study was to evaluate the results of fluorescence angiography for assessing anastomotic perfusion after resection of the sigmoid colon and rectum since its introduction into clinical practice at the authors´ workplace and to evaluate the incidence of necessary resection line repositioning based on the quality of perfusion, and also to record any complications in anastomotic healing.

METHOD

Retrospective unicentric analysis of prospectively collected data from patients with resection of the sigmoid colon and rectum with primary anastomosis. The patient set included 50 patients, 27 males and 23 females; the median age was 64.5 years (33-80). Forty-four patients were indicated for resection for cancer of the sigmoid colon or rectum, while 6 patients had a benign disease. Twenty-nine patients underwent total mesorectal excision with coloanal mechanical or hand-sewn anastomosis and 21 underwent resection of the sigmoid colon or upper rectum with mechanical anastomosis. Prior to the construction of the anastomosis, assessment of perfusion of the anastomotic segments by near infrared (NIR) indocyanine green (ICG) fluorescence angiography was performed in all patients. The quality of perfusion of the mesocolon and bowel wall and its impact on moving the resection line and complications of anastomotic healing 30 days postoperatively were all evaluated.

RESULTS

Assessment of perfusion using fluorescence angiography was technically successfully performed in all 50 patients. In 5 cases (10%) the resection line had to be moved for signs of poor perfusion of the bowel wall. Postoperatively, healing of the anastomosis was complicated in four patients (8%). Dehiscence was recorded in 3 patients (10.3%) with total mesorectal excision and in 1 patient (4.8%) after resection of the sigmoid colon and upper rectum.

CONCLUSION

The presented results indicate that fluorescence angiography may lead to a decrease in the incidence of anastomotic dehiscence after colorectal resections by mapping in detail the perfusion of the anastomosed segments.Key words: fluorescence angiography - indocyanine green - anastomotic leak - colorectal resection.

[Transanal total mesorectal excision for low rectal cancer - first results]

INTRODUCTION

First experiences with laparoscopic low anterior resection with transanal mesorectal excision in patients with low and mid rectal cancer are referred.

METHODS

During a 9 month period (between October 2013 and May 2014), 17 laparoscopically assisted rectal resections with transanal total mesorectal excision, hand-sewn colo-anal anastomosis and protective ileostomy were performed at two institutions (CHK FN Brno, CHO KOC Nový Jičín). There were 11 males and 6 females, with a mean age 68 years (range 49-81 years) in our cohort. The tumor was located 30-80mm from the anal verge (median 60 mm).

RESULTS

A negative distal resection margin was achieved in all patients. The circumferential resection margin was positive in two cases. The TME quality was described as complete in 8 cases and nearly complete in 9 cases. Mean operative time was 280 min (range 212-375 min) with no intra-operative complications. Anastomotic leakage was observed in two patients (12%). Median length of postoperative hospital stay was 9 days with a range of 6-30 days, in case of anastomotic and wound complications.

CONCLUSION

According to our first experience we evaluated this method as feasible and safe with satisfactory pathological outcomes. We cannot recommend exact indications yet. It is assumed that the transanal approach for total mesorectal excision should be indicated in obese patients with a narrow pelvis and voluminous prostate.Key words: total mesorectal excision transanal minimally invasive surgery.

[Transanal total mesorectal excision for rectal cancer - just a fashion trend?]

Transanal total mesorectal excision performed using equipment for transanal minimally invasive surgery is an innovative surgical technique introduced to facilitate this procedure and to reach better oncosurgical outcomes in patients with low rectal cancer. This article presents a brief summary of guidelines for treatment of patients with low rectal carcinoma. Up-to-date information about the principles of this new method, its modifications and contemporary indications is presented. Based on their own experience and literature resources, the authors inform about the advantages, limitations and unresolved issues of minimally invasive transanal mesorectal excision.

[Laparoscopic parastomal hernia repair with modified Sugarbaker technique in patients after abdominoperineal resection of the rectum - initial experience]

INTRODUCTION

Parastomal hernia is a common stoma complication. Surgical treatment is necessary in approximately 10 to 20% of cases. Mesh hernia repair gives significantly better results. The authors present their initial experience with laparoscopic repair of parastomal hernia using the modified Sugarbaker technique.

MATERIAL AND METHODS

In the period from January 2011 to December 2013, 15 patients with a symptomatic parastomal hernia underwent laparoscopic repair with modified Sugarbaker technique. All patients had a parastomal hernia at the site of terminal colostomy after abdominoperineal resection. 14 patients underwent primary hernia repair, 1 patient was operated on for recurrence of parastomal hernia after open hernia repair. Parietex Parastomal mesh was used for hernia repair in all cases.

RESULTS

Laparoscopic repair was performed successfully in all patients. The mean operating time was 45 minutes (range: 2080 minutes). The mean postoperative hospital stay was 3 days (range: 26 days). No serious postoperative complication was recorded. In the postoperative period, a recurrent symptomatic hernia was found in 1 of 15 patients (6.7%) with reintervention 17 months after primary surgery.

CONCLUSION

Laparoscopic hernia repair of parastomal hernia with modified Sugarbaker technique seems to be a safe method with a very low risk of postoperative complications, including hernia recurrence. .

[Tibiocalcaneal arthrodesis with retrograde nails. Description of a hindfoot procedure after massive talus destruction]

Following loss of the talus, tibiocalcaneal fusion is often the only available means of obtaining weight-bearing ability in the lower limb. Length discrepancy may be managed with an allograft. This casuistic describes 6 patients with tibiocalcaneal fusion (mean age 64 years) who had received a structural femoral head allograft fusion for failed total ankle arthroplasty (3 cases), Charcot arthropathy (2 cases) and osteomyelitis (1 case). The mean follow-up was 33 months and all limbs could be salvaged. There were two cases of non-union (one with infection). The mean AOFAS score was 51 and the mean Mazur score was 37. In the SF-36 the mean PCS was 34.4 and the mean MCS was 48.4. It was shown that in the hindfoot, as at other sites, allografts may be used for the filling of major bone defects; however, the patient function will still be massively impaired. Therefore, the procedure should be confined to cases where less complex and less invasive techniques are unlikely to be of benefit.

[STARR surgery in the treatment of rectocele and rectal intussusception]

INTRODUCTION

Rectocele and intussusceptions are amongst the most frequent causes of Obstructed Defecation Syndrome (ODS). ODS diagnostics has been constantly improving which results in more precise indication criteria for individual surgical approaches. The work discusses indications for Stapled TransAnal Rectal Resection (STARR) as well as the results of the seven-year follow-up.

MATERIAL AND METHODS

Female patients with ODS score over 7 were indicated for STARR procedure after all conservative treatment possibilities failed. The proper indication requires that other causes of ODS be excluded. The retrospective analysis of prospectively collected data was employed.

RESULTS

Between January 2005 and October 2012 29 STARR procedures for rectocele were performed. Morbidity rate of the set of our patients was 6.9%. None of the patients died. We recorded bleeding from the staple line in seven patients (without surgical revision), and urinary infection in two patients. Bleeding from staple line was present in seven causes and urinary infection was present twice.

CONCLUSION

The STARR procedure seems to be an effective and safe treatment for ODS associated with rectocele and intussusception. The overall morbidity rate is low. Further investigation is required to optimize patient's selection and to reduce the potential complications and failure during postoperative period.

[Comparative study on the strength of different mechanisms of operation of multidirectionally angle-stable distal radius plates]

INTRODUCTION

Polyaxial angle-stable plating is thought to be particularly beneficial in the management of complex intra-articular fractures of the distal radius. The present study was performed to investigate the strength of polyaxial locking interfaces of distal radius plates.

MATERIAL AND METHODS

We tested the polyaxial interfaces of 3 different distal radius plates (2.4 mm Variable Angle LCP Two-Column Volar Distal Radius Plate, Synthes, Palmar Classic, Königsee Implantate and VariAx Plate Stryker). The strength of 0° and 10° screw locking angle was obtained during static loading.

RESULTS

The strength of Palmar Classic with a 0° locking angle is significantly the best of all tested systems. With a 10° locking angle there is no significant difference between Palmar Classic, Two column Plate and VariAx Plate.

CONCLUSION

The strength of polyaxial interfaces differs between the tested systems. A reduction of ultimate strength is due to increases of screw locking angle. The design of polyaxial locking interfaces should be investigated in human bone models.

[Sustentaculum tali screw placement for calcaneus fractures--different navigation procedures compared to the conventional technique]

AIM

Precise placement of the sustentaculum tali screw is essential for fixation of calcaneus fractures to achieve the best fixation strength. In the clinical practice, this procedure is demanding due to the complex anatomic configuration of the calcaneus and the limited visualisation in the intraoperative fluoroscopic images. The aim of this study was an evaluation of the accuracy for the sustentaculum tali screw placement by using different navigation procedures compared to the standard procedure. The different navigation specific workflows were evaluated and the feasibility of each procedure proven in clinical applications.

METHOD

Eight sustentaculum screws per group were placed in an artifical Synbone model. Different navigation procedures were evaluated: 2D-fluoroscopy (group I), 3D-fluoroscopy (group II), fluoro-free (group III) and compared to the conventional screw placement without navigation (group IV). For each screw the time of fluoroscopy and the duration of the procedure were measured. The accuracy was evaluated postoperatively by computed tomography using axial slices and coronary as well as sagittal reformations. Furthermore, the workflow of each navigation procedure was analysed and proven in clinical applications.

RESULTS

In the experimental setup, no radiation exposure was mandatory for the conventional and fluoro-free procedures, whereas mean fluoroscopy times of 17 +/- 1.03 und 66.8 +/- 0.9 were measured for 2D- and 3D-navigation procedures. In line with this, the overall mean procedure times for the screw placement were 1.26 +/- 0.05 (group IV), 3.49 +/- 0.26 (group III), 13.32 +/- 0.49 (group I) und 19.04 +/- 1.41 minutes (group II). No significant differences were observed for the accuracy of screw placement. In the clinical practice a better orientation was achieved by use of a navigation system. The fluoro-free procedure can be easily integrated into the common operation workflow, whereas the workflow of both image-based navigation procedures is technically demanding.

CONCLUSION

Navigation procedures seem to be helpful for the precise placement of sustentaculum tali screws in cases of operative calcaneus fracture fixation. The kind of application to be used depends on the infrastructure of the department and the navigation-experience of the operating room team. Whereas the fluoro-free procedure is intuitive in use, the 2D-navigation does not justify the extra efforts. The 3D-procedure is the recommended application for surgeons familiar with navigation, providing the best orientation due to the slice image visualisation in all three dimensions.

Multiple signaling pathways involved in activation of matrix metalloproteinase-9 (MMP-9) by heregulin-beta1 in human breast cancer cells

Matrix metalloproteinase-9 (MMP-9) plays important roles in tumor invasion and angiogenesis. Secretion of MMP-9 has been reported in various cancer types including lung cancer, colon cancer, and breast cancer. In our investigation of MMP-9 regulation by growth factors, MMP-9 was activated by heregulin-beta1 as shown by zymography in both SKBr3 and MCF-7 breast cancer cell lines. Increase in MMP-9 activity was due to increased MMP-9 protein and mRNA levels, which mainly results from transcriptional upregulation of MMP-9 by heregulin-beta1. Heregulin-beta1 activates multiple signaling pathways in breast cancer cells, including Erk, p38 kinase, PKC, and PI3-K pathways. We examined the pathways involved in heregulin-beta1-mediated MMP-9 activation using chemical inhibitors that specifically inhibit each of these heregulin-beta1-activated pathways. The PKC inhibitor RO318220 and p38 kinase inhibitor SB203580 completely blocked heregulin-beta1-mediated activation of MMP-9. MEK-1 inhibitor PD098059 partially blocked MMP-9 activation, whereas PI3-K inhibitor wortmannin had no effect on heregulin-beta1-mediated MMP-9 activation. Therefore, at least three signaling pathways are involved in the activation of MMP-9 by heregulin-beta1. Since MMP-9 is tightly associated with invasion/metastasis and angiogenesis, our studies suggest that blocking heregulin-beta1-mediated activation of MMP-9 by inhibiting the related signaling pathways may provide new strategies for inhibition of cancer metastasis and angiogenesis.