Comparison of the fixation ability of headless compression screws and locking plate for metacarpal shaft transverse fracture

Metacarpal shaft fractures are common hand fractures. Although bone plates possess strong fixation ability, they have several limitations. The use of headless compression screws for fracture repair has been reported, but their fixation ability has not been understood clearly.This study aimed to compare the fixation ability of locked plate with that of headless compression screw for metacarpal fracture repair.A total of 14 artificial metacarpal bones (Sawbones, Vashon, WA, USA) were subjected to transverse metacarpal shaft fractures and divided into 2 groups. The first group of bones was fixed using locked plates (LP group), whereas the second group was fixed using headless compression screws (HC group). A material testing machine was used to perform cantilever bending tests, whereby maximum fracture force and stiffness were measured. The fixation methods were compared by conducting a Mann-Whitney U test.The maximum fracture force of the HC group (285.6 ± 57.3 N, median + interquartile range) was significantly higher than that of the LP group (227.8 ± 37.5 N; P < .05). The median of the HC group was 25.4% greater. However, no significant difference in stiffness (P > .05) was observed between the HC (65.2 ± 24.6 N/mm) and LP (61.7 ± 19.7 N/mm) groups.Headless compression screws exhibited greater fixability than did locked plates, particularly in its resistance to maximum fracture force.

Fractured coracoid process with acromioclavicular joint dislocation: A case report

RATIONALE

Coracoid processes (CPs) fracture with acromioclavicular (AC) joint dislocation are extremely rare. This combined injury has brought many challenges to surgeons, and the mechanism underlying the injury is still not fully understood. There is no clear consensus on its treatment.

PATIENT CONCERNS

Here, we describe a CP fracture with AC joint dislocation in a middle-aged manual worker.

DIAGNOSIS

Radiographs showed a fracture of the base of the CP and a third-degree AC joint separation.

INTERVENTIONS

The patient was treated surgically with open reduction and internal fixation of the AC joint by LCP clavicle hook plate, and the CP was fixed with a 3.5 mm diameter cannulated screw.

OUTCOMES

Three months after the operation, shoulder function was completely restored, and the affected shoulder had full mobility with no tenderness. Plain film radiography showed anatomical indications of the healing of these combined injuries.

LESSONS

Although AC joint dislocation with CP fractures is extremely rare in adults, it is important to remind and remember that this possibility exists. In unclear cases, special radiographic films and CT are necessary. Surgical treatment of AC joint dislocation with CP fractures can provide solid stability and restore normal shoulder function with an excellent prognosis.

Distal third femoral shaft fractures in school-aged children: A comparative study of elastic stable intramedullary nail and external fixator

Internal fixation such as elastic stable intramedullary(ESIN) nail and submuscular plate (SMP) is gaining popularity for femoral shaft fractures in school-aged children. However, external fixation (ExFix) might be a valuable option for the distal third femoral shaft fractures, where the fracture heals rapidly, but it is crucial to avoid angular malunion. This study aims to compare the clinical outcomes, postoperative complications of distal third femoral shaft fractures in school-aged children treated by ESIN versus ExFix.Patients aged 5 to 11 years with distal third femoral shaft fractures treated at our institute from January 2014 to January 2016 were included and categorized into ESIN (n = 33) and ExFix (n = 38) group. The preoperative data, including baseline information of the patients, radiographic parameters, and type of surgical procedure, were collected from the hospital database, and postoperative data, including complications, were collected during the follow-up visit.In all, 33 patients (average, 8.0 ± 2.1 years, male 20, female 13) in the ESIN group and 38 patients (average, 8.3 ± 2.3 years, male 23, female 15) in the ExFix group were included in this study. There was significantly less operative time for the ExFix group (45.4 ± 7.8 min) as compared to the ESIN group (57.8 ± 11.3 min) (P < .01), reduced estimated blood loss (EBL) in the ExFix group (9.9 ± 3.5) as compared to the ESIN group (16.4 ± 6.5) (P < .01). As for the frequency of fluoroscopy, there was a significant difference between the ExFix group (13.9 ± 2.4) and the ESIN group (15.5 ± 3.2) (P = .02). The rate of major complications was not significantly different between the 2 groups (P = .19). The rate of implant irritation was significantly higher in the ExFix group (28/38, 73.7%) than the ESIN group (12/33, 36.4%) (P < .01). The rate of surgical site infection (SSI) is significantly higher in the ExFix group (18/38, 47.4%)) than the ESIN group (1/33, 3%) (P < .01). The rate of scar concern was significantly higher in the ExFix (9/38, 23.7%) than the ESIN (2/33, 6.1%), (P = .04). According to the Flynn scoring system, 30(90.9%) patients in the ESIN group and 24(89.5%) patients in the ExFix group were rated as excellent. None of the patients had poor outcomes.Both ESIN and ExFix produced satisfactory outcomes in distal third femoral shaft fractures. ExFix remains a viable choice for selected cases, especially in resource-challenged and austere settings.

Comparison of two reinforcement rings for primary total hip arthroplasty addressing displaced acetabular fractures: a biomechanical analysis

INTRODUCTION

Aim of this study was to biomechanically compare two different acetabular cup fixation constructs in terms of fracture fixation for displaced acetabular fractures involving the anterior column with hemitransverse fracture under partial and full weight-bearing conditions.

METHODS

Two different reinforcement rings designed as cages for primary THA were biomechanically tested in terms of managing a complex acetabular fracture. Single-leg stance cyclic loading was performed to assess fracture gap movement and fragment rotation. Twelve hemi pelvis Sawbones were divided into two groups: primary THA with acetabulum roof reinforcement plate (ARRP) (n = 6) and primary THA with Burch-Schneider reinforcement cage (BSRC) (n = 6).

RESULTS

During loading under partial weight-bearing (250 N) fracture gap movement tended to be larger in the BSRC group as compared to the ARRP group. Under full weight-bearing conditions, the ARRP showed 60% significantly less motion (p = 0.035) of the os ilium to os ischii gap compared to BSRC. Fracture gap movements between the os ilium and spina iliaca fragments were significantly reduced by 76% (p = 0.048) for ARRP in contrast to BSRC. The ARRP group also demonstrated significantly less movement in the fracture gaps os ischii to quadrilateral plate (62% reduction, p = 0.009) and quadrilateral plate to spina iliaca (87% reduction, p < 0.001). Significantly less rotational movement of the quadrilateral plate to the os ilium was exhibited by the ARRP group (p = 0.015).

CONCLUSIONS

The presented acetabulum roof-reinforcement plate (ARRP) provides stable conditions at the acetabular component with adequate stabilization of a displaced acetabular fracture.

Comparison of the efficacy of a distal clavicular locking plate with and without a suture anchor in the treatment of Neer IIb distal clavicle fractures

BACKGROUND

To compare the clinical outcomes between the use of a distal clavicular locking plate alone and the combined use of a plate and a coracoclavicular suture anchor in the treatment of Neer IIb distal clavicle fractures and to discuss the application procedure of suture anchors.

METHODS

This is a retrospective study. Thirty-four patients with unilateral Neer IIb distal clavicle fractures who underwent open reduction and internal fixation with a distal clavicular locking plate only (16 patients) or with both a plate and a coracoclavicular suture anchor (18 patients) were evaluated. The main observation data included the Constant-Murley Shoulder Function Score (CMS), rate of postoperative complications, and union time.

RESULTS

The distal clavicular locking plate and coracoclavicular suture anchor combination group had better outcomes in the Constant-Murley score (94.6 ± 4.5 vs. 90.1 ± 9.5) (P < 0.05) and a shorter union time (13.9 ± 2.3 vs. 16.1 ± 3.0) (P < 0.05) than the locking plate only group did, and the rate of complications showed no significant difference, 16.7% vs. 31.2% (5/16) (P>0.05).

CONCLUSIONS

Both methods achieved good results in the treatment of Neer IIb distal clavicle fractures; however, the use of both locking plates and coracoclavicular suture anchors can provide more stability in the early stage after operation than can the use of locking plates alone, which can make the sped of union quicker and result in better clinical outcomes. For elderly patients with comminuted Neer IIb distal clavicle fractures, a locking plate combined with a suture anchor is recommended to provide more stability in the early stage after the operation.

Distal Radius Allograft Reconstruction Utilizing a Step-Cut Technique After En Bloc Tumor Resection

Background: En bloc resection of the distal radius is a common treatment for advanced and recurrent giant cell tumors and less commonly for sarcoma. Various reconstructive options exist, including ulnar transposition, osteoarticular autograft and allograft, and allograft arthrodesis. We present a technique of reconstruction using a distal radius bulk allograft with a step-cut to allow for precise restoration of proper length and to promote bony union. Methods: Preoperative templating is performed with affected and contralateral radiographs to assess the size of the expected bony defect, location of the step-cut, and the optimal size of the distal radius allograft required. A standard dorsal approach to the distal radius is utilized, and the tumor is resected. A proximal row carpectomy is performed, and the plate/allograft construct is applied to the remaining host bone. Iliac crest bone graft is harvested and introduced at the graft-bone interface and radiocarpal arthrodesis sites. Results: We have previously reported outstanding union rates with the step-cut technique compared with a standard transverse cut. Conclusions: The technique described provides reproducible union and stabilization of the wrist and forearm with adequate function following en bloc resection of the distal radius for tumor.

Successful management of lower limb nonunion using locking plates and bone graft with retention of intramedullary nail

This study aims to investigate the clinical effect of the combined an additional locking plate with bone graft based on retaining the original intramedullary nail for the treatment of lower limb nonunion.From June 2008 to December 2012, 39 patients were admitted and treated, who developed non-infectious bone nonunion after intramedullary nail fixation for long bone fracture in the lower limb. Additional locking plate and autogenous iliac bone grafting were performed for these patients, in which the original intramedullary nail was retained. Follow-ups were performed once at postoperative months 1, 2, 3, 6, and 12, and every year onwards. During these follow-ups, imaging and clinical function examinations were performed, in order to observe callus growth and the fractured limb functions.All patients have been followed-up, in which the duration of these follow-ups ranged between 8 and 24 months. All patients gained bony union within 6 to 11 months, and the healing rate was 100%. Radiographic healing time ranged between 8 and 15 months. Full weight-bearing time ranged between 2 and 10 months. According to Harris hip scores and Hospital for Special Surgery (HSS) Knee joint scores, 17 cases were excellent, 2 cases were good, and 1 case was acceptable; with an excellent and good rate of 95.00%. According to HHS score for the knee, 15 cases were excellent, 3 cases were good, and 1 case was acceptable; with an excellent and good rate of 94.74%.The combined treatment of the additional blocking plate with bone grafting based on retaining the original intramedullary nail for bone nonunion could effectively eliminate lateral and rotatory instability of the fractured ends. This surgical method had a short operation time, high healing rate and other advantages.

Retrospective evaluation of perioperative and short term clinical outcomes in appendicular long bone skeleton fractures repaired via the string of pearls (SOP) locking plate system

BACKGROUND

Internal plate fixation and, more recently, locking plate fixation are commonly used in the repair of fractures in small animal surgery. This retrospective study reviewed the use of the String of Pearls locking plate system in the fixation/repair of appendicular long bone skeleton fractures in 31 small animal veterinary patients (33 fractures).

RESULTS

Major complications necessitating revision surgery occurred in 7/33 (21%), with implant failure as the inciting cause in all cases. Variables corresponding to an unsuccessful outcome were evaluated, and a correlation was found with plates placed in a bridging manner (placed without rigid anatomic reconstruction, p = 0.02) and length of follow-up (p = 0.01).

CONCLUSIONS

The SOP plating system can be used in the repair of appendicular longbone skeletal fractures, however, the authors propose that adjunct fixation, such as intramedullary pin, double plating, or external coaptation would likely improve results and should be considered imperative in cases in which anatomic reconstruction is either not desirable or achievable.

Osteosynthesis with Locking Plate for Proximal Humerus Fracture

Background Approximately 5% of all fractures consists of proximal humeral fractures. In the elderly population, most of these fractures are related to osteoporosis. Internal fixation has led to unpredictable results, especially in patients with osteopenic bone and those with comminuted fractures. Objective To evaluate functional outcome and complications following proximal humerus fracture fixation using locking plate. Method This prospective observational study was conducted at Nepal Medical College and Teaching Hospital from February 2014 to June 2015. We reviewed 35 patients with proximal humerus fractures, who underwent open reduction and internal fixation with locking plate.Functional outcome was evaluated according to the ConstantMurley shoulder assessment. Result Fracture union was achieved in all cases with the mean time to union being 14.6 weeks (11-24 weeks). At the final follow up the mean constant murley score was 73.6 (48-94). There was total 8(22.85%) cases who developed complication. Conclusion Internal fixation with the locking plate for proximal humerus fractures provides stable construct with better functional outcome as it allows early shoulder mobilization.

Evaluation of Anterolateral Plating of Distal Third Tibial Fractures

Background Distal one-third tibial fractures with or without articular involvement can be difficult to manage. Variety of treatment methods have been suggested for these injuries, including conservative treatment, external fixation with or without limited internal fixation, intramedullary nailing, plate fixation (medial or anterolateral) and more recently minimally invasive plate osteosynthesis (MIPO). All of these techniques have advantages and disadvantages. None of these techniques can be considered the "gold standard" for these injuries. Objective The objective of this prospective study was to evaluate the results of anterolateral plating of these fractures. Method Forty-five fractures of distal third of tibia were treated with open reduction and internal fixation with anterolateral tibial plate from December 2011 to December 2016. All the patients were followed up at least for nine months for the study. Radiological union was finally assessed in nine months. Result All the fractures united within nine months of plating without angulation in sagittal or coronal plane. One patient (2%) had limb length shortening of more than one cm. Full range of motion of ankle and knee joint was achieved compared to the normal side by nine months follow up. 17 (38%) patients developed marginal skin necrosis. Three (7%) patients developed superficial wound infection. These complications were seen more in patients in whom posterior below knee slab was used for pre-operative splintage (as compared to calcaneal traction). Conclusion Hence distal one-third tibial fractures with or without articular involvement can be treated with anterolateral tibial plate.

Prototype of a Silicon Nitride Ceramic-Based Miniplate Osteofixation System for the Midface

OBJECTIVE: The favorable properties of silicon nitride (Si3N4) ceramics, such as high mean strength level and fracture toughness, suggest biomedical use as an implant material. Minor reservations about the biocompatibility of Si3N4 ceramics were cleared up by previous in vitro and in vivo investigations.

STUDY DESIGN AND SETTING: A Si3N4 prototype mini-fixation system was manufactured and implanted for osteosynthesis of artificial frontal bone defects in 3 minipigs. After 3 months, histological sections, computed tomography (CT) scans, and magnetic resonance imaging (MRI) scans were obtained. Finite element modeling (FEM) was used to simulate stresses and strains on Si3N4 miniplates and screws to calculate survival probabilities.

RESULTS: Si3N4 miniplates and screws showed satisfying intraoperative workability. There was no implant loss, displacement, or fracture. Bone healing was complete in all animals. The formation of new bone was observed in direct contact to the implants. The implants showed no artifacts on CT and MRI scanning. FEM simulation confirmed the mechanical reliability of the screws, whereas simulated plate geometries regarding pullout forces at maximum load showed limited safety in a bending situation.

CONCLUSIONS: Si3N4 ceramics show a good biocompatibility outcome both in vitro and in vivo. In ENT surgery, this ceramic may serve as a biomaterial for osteosynthesis (eg, of the midface including reconstruction the floor of the orbit and the skull base). To our knowledge, this is the first introduction of a ceramic-based miniplate-osteofixation system. Advantages compared with titanium are no risk of implantation to bone with mucosal attachment, no need for explantation, and no interference with radiologic imaging. Disadvantages include the impossibility of individual bending of the miniplates.

Impact of screw location and endplate preparation on pullout strength for anterior plates and integrated fixation cages

BACKGROUND CONTEXT

Numerous integrated fixation cages (IFCs) have recently been introduced to the market with "zero-profile" designs that incorporate screw fixation through the vertebral endplate. It is unclear whether differences in bone quality and quantity in this insertion location may affect fixation compared with screws used in traditional anterior plate (AP) fixation. Moreover, endplate preparation for IFC implantation may affect fixation strength.

PURPOSE

This study aimed to compare pullout strength of screws used in IFCs with screws used for AP implantations.

STUDY DESIGN

A biomechanical cadaveric study.

METHODS

T12 and L1 vertebrae from 13 human cadaver spines were prepared for pullout testing. End plates in T12 vertebrae were scraped according to surgical practice for fusion procedures. Conversely, endplates in L1 vertebrae were kept intact (unscraped). Integrated fixation cage screws were implanted at a 45° angle into the endplate and AP screws were implanted horizontally into the same vertebral body. Pullout testing was performed on all screws, and peak pullout force (PPF) and work were compared between groups to determine fixation strength. In addition, micro-CT imaging was used to assess bone quantity and quality parameters such as trabecular bone volume fraction, endplate and anterior cortex thickness at screw insertion location, endplate mineralization, and anterior cortex mineralization.

RESULTS

Peak pullout force for IFC screws (176±68 N) with scraped endplates was similar (p=.26) to AP screws (192±84 N). However, PPF for IFC screws (231±75 N) with unscraped endplates was significantly greater (p<.01) than AP screws (176±50 N). Peak pullout force for IFC screws with scraped endplates was significantly lower (p=.03) than IFC screws with unscraped endplates. Scraped endplates group (0.17±0.05 mm) were thinner (p=.05) than unscraped endplates (0.21±0.06 mm) by approximately 40 µ on average.

CONCLUSIONS

These data indicate that IFC and AP screws exhibited similar fixation behavior when the endplate is prepared according to common surgical practices. However, endplate scraping reduces endplate thickness by 20% on average, resulting in a decrease in fixation strength when compared with the unscraped endplates and provides bounds for IFC screw fixation strength.

Clinical comparative analysis on unstable pelvic fractures in the treatment with percutaneous sacroiliac screws and sacroiliac joint anterior plate fixation

OBJECTIVE

To investigate clinical efficacy of unstable pelvic fractures in the treatment with percutaneous sacroiliac screws and sacroiliac joint anterior plate fixation.

PATIENTS AND METHODS

64 patients with unstable pelvic fractures were selected in the hospital from January 2008 to June 2011, and were randomly divided into two groups.(32 patients with sacroiliac anterior plate fixation as the control group, and another 32 patients with percutaneous sacroiliac screw internal fixation as the observation group). The perioperative period clinical indicators, postoperative Matta score, postoperative Majeed function score of all patients were compared and analyzed.

RESULTS

The operation time, intraoperative blood loss, wound total length, postoperative fever time, duration of hospitalization in the observation group were significantly less than those in the control group. The complication rate (3.1%) in the observation group was lower than that in the control group (21.9%). The rate of Matta score excellent (96.9%) in the observation group was higher than that in the control group (81.2%) after the treatment. The rate of Majeed function score excellent (93.8%) in the observation group was significantly higher than that in the control group (75%) after the treatment.

CONCLUSIONS

Percutaneous sacroiliac screw internal fixation in the treatment of unstable pelvic fractures has less injury, less bleeding, less pain and rapid recovery which is a safe and effective minimally invasive operation method. The clinical curative effect of percutaneous sacroiliac screw internal fixation is better than anterior plate fixation for the treatment of sacroiliac joint. The full preparation before the surgery and patients with positive can substantially reduce the occurrence of complications rate.

Biomechanical comparison of the Locking Compression superior anterior clavicle plate with seven and ten hole reconstruction plates in midshaft clavicle fracture stabilisation

PURPOSE

The purpose of this study was to characterise the biomechanical properties of the seven hole superior anterior clavicle LCP (locking compression plate) and to compare these with the properties of commonly applied implants used for the stabilisation of clavicular midshaft fractures such as the locking 7- and ten hole reconstruction plate.

METHODS

Twenty-four synthetic clavicles were used. A transverse midshaft fracture was induced. The clavicles were fixed with angle stable clavicle LCPs, seven hole and ten hole reconstruction plates (n = 8 each). Twenty cycles of axial compression and torsion were performed for each sample, which was followed by 1,000 cycles of three point bending and ultimately bending to failure. Axial, torsional and cantilever bending stiffness were calculated from the data recorded.

RESULTS

The clavicle LCP showed the highest overall stiffness compared to the seven and ten hole reconstruction plate. Significantly higher stiffness values were found for axial compression and external rotation. In the load-to-failure tests, the ten hole reconstruction plate especially showed early signs of plastic deformation, which might account for early plate insufficiency so frequently observed clinically.

CONCLUSION

The results indicate that the clavicle LCP, as compared to the reconstruction plates, leads to superior biomechanical stability in the treatment of midshaft clavicle fractures.

Biomechanical analysis of a new expandable vertebral body replacement combined with a new polyaxial antero-lateral plate and/or pedicle screws and rods

PURPOSE

Restoration of the anterior spinal profile and regular load-bearing is the main goal treating anterior spinal defects in case of fracture. Over the past years, development and clinical usage of cages for vertebral body replacement have increased rapidly. For an enhanced stabilization of rotationally unstable fractures, additional antero-lateral implants are common. The purpose of this study was the evaluation of the biomechanical behaviour of a recently modified, in situ distractible vertebral body replacement (VBR) combined with a newly developed antero-lateral polyaxial plate and/or pedicle screws and rods using a full corpectomy model as fracture simulation.

METHODS

Twelve human spinal specimens (Th12-L4) were tested in a six-degree-of-freedom spine tester applying pure moments of 7.5 Nm to evaluate the stiffness of three different test instrumentations using a total corpectomy L2 model: (1) VBR+antero-lateral plate; (2) VBR, antero-lateral plate+pedicle screws and rods and (3) VBR+pedicle screws and rods.

RESULTS

In the presented total corpectomy defect model, only the combined antero-posterior instrumentation (VBR, antero-lateral plate+pedicle screws and rods) could achieve higher stiffness in all three-movement planes than the intact specimen. In axial rotation, neither isolated anterior instrumentation (VBR+antero-lateral plate) nor isolated posterior instrumentation (VBR+pedicle screws and rods) could stabilize the total corpectomy compared to the intact state.

CONCLUSIONS

For rotationally unstable vertebral body fractures, only combined antero-posterior instrumentation could significantly decrease the range of motion (ROM) in all motion planes compared to the intact state.

Hemiarthroplasty versus angle-stable locking compression plate osteosynthesis in the treatment of three- and four-part fractures of the proximal humerus in the elderly: design of a randomized controlled trial

BACKGROUND

The optimal surgical management of dislocated three- and four-part fractures of the proximal humerus in elderly patients remains unclear. Most used techniques are hemiarthroplasty and angle-stable locking compression plate osteosynthesis. In the current literature there is no evidence available presenting superior results between hemiarthroplasty and angle-stable locking compression plate osteosynthesis in terms of speed of recovery, pain, patient satisfaction, functional outcome, quality of life or complications.

METHODS/DESIGN

A randomized controlled multicenter trial will be conducted. Patients older than 60 years of age with a dislocated three- or four-part fracture of the proximal humerus as diagnosed by X-rays and CT-scans will be included. Exclusion criteria are a fracture older than 14 days, multiple comorbidity, multitrauma, a pathological fracture, previous surgery on the injured shoulder, severely deranged function caused by a previous disease, "head-split" proximal humerus fracture and unwillingness or inability to follow instructions. Participants will be randomized between surgical treatment with hemiarthroplasty and angle-stable locking compression plate osteosynthesis. Measurements will take place preoperatively and 3 months, 6 months, 9 months, 12 months and 24 months postoperatively. Primary outcome measure is speed of recovery of functional capacity of the affected upper limb using the Disabilities of Arm, Shoulder and Hand score (DASH). Secondary outcome measures are pain, patient satisfaction, shoulder function, quality of life, radiological evaluation and complications. Data will be analyzed on an intention-to-treat basis, using univariate and multivariate analyses.

DISCUSSION

Both hemiarthroplasty and angle-stable locking compression plate osteosynthesis are used in the current treatment of dislocated three-and four-part fractures of the proximal humerus. There is a lack of level-1 studies comparing these two most-used surgical treatment options. This randomized controlled multicenter trial has been designed to determine which surgical treatment option provides the fastest recovery of functional capacity of the affected upper limb, and will provide better outcomes in pain, satisfaction, shoulder function, quality of life, radiological evaluation and complications.

TRIAL REGISTRATION NUMBER

The trial is registered in the Netherlands Trial Registry (NTR2461).

[The radical minimal access thoracoplasty by funnel chest in adults]

A new technique of radical thoracoplasty, performed with a small size incision, using the sternocostal complex fixation with nitinol plates with shape memory and the surgical toolkit required for the purpose, has been successfully introduced. 23 patients underwent surgery using the technique. Tree patients had early postoperative complications: 2 cases of exudative pleurisy and 1 case of bronchitis aggravation. Good cosmetic results was achieved in all operated patients. The mechanical ground of the technique is based on the use of the effective force of the sternum traction and the pressure of the plate on the tissues below. The main advantage of the method is avoidance of the transverse sternotomy.

Vertebral reconstruction using the telescopic plate spacer-thoracolumbar (TPS-TL) device

STUDY DESIGN

Retrospective study of surgical technique and outcome.

OBJECTIVE

The authors conducted a study to evaluate the ability of the TPS-TL (telescopic plate spacer-thoracolumbar) implant to correct kyphotic deformity and restore vertebral body height after vertebrectomy in the thoracolumbar spine.

SUMMARY OF BACKGROUND DATA

TPS-TL is a novel vertebral body replacement device that consists of an expandable cage with an integrated plate component for transvertebral screw fixation.

METHODS

This is a retrospective study of 20 patients who underwent anterior column reconstruction with TPS-TL after a 1 or 2 level thoracolumbar vertebrectomy. Preoperative and postoperative sagittal alignment and vertebral body heights were radiologically analyzed in all patients. The mean follow-up was 14 months.

RESULTS

Preoperative and postoperative Cobb angles were measured to assess sagittal alignment. The average preoperative Cobb angle was 16.0 + or - 7 degrees. This was reduced to 9.8 + or - 10 degrees at the final follow-up (P<0.001). Percent of ideal vertebral body height was used to assess postoperative restoration of vertebral body height. This value was obtained by creating a ratio of the height of the effected vertebral levels to the height of the adjacent normal vertebral bodies. The mean percent of ideal vertebral body height improved from a preoperative value from 86.2 + or - 2% to 93.1 + or - 6% at the final follow-up (P<0.001).

CONCLUSIONS

The TPS-TL implant is effective in restoring vertebral body height and correcting kyphotic deformity after thoracolumbar vertebrectomy.

Biomechanical analysis of expansion screws and cortical screws used for ventral plate fixation on the cervical spine

Compared to bicortical screws, the surgical risk of injuring intraspinal structures can be minimized with the use of monocortical screws. However, this reduction should not be achieved at the expense of the stability of the fixation. With monocortical stabilization, the expansion screws have the potential of absorbing high loads. Therefore, they are expected to be a suitable alternative to bicortical screws for revision surgeries and in osteoporotic bone. The purpose of this in vitro study was to investigate the stiffness of the two screw-plate systems used for ventral stabilization of the cervical spine, by focusing on the suitability of expansion screws as tools for revision treatments. The study was conducted in ten functional units of human cervical spines. The device sample stiffness was determined for four conditions using a turning moment of 2.25 N m each around one of the three principle axes. The conditions were native, destabilized, primarily stabilized with one of the screw-plate systems, followed by secondary stabilization using the expansion screw implant. The stabilized samples achieved a comparable, in most cases higher stiffness than the native samples. The samples undergoing secondary stabilization using expansion screws tend to display greater stiffness for all three axes compared to the primarily stabilized samples. The achieved tightening moment of the screws was higher than the one achieved with primary fixation. Both plates revealed similar primary stability. Revision surgeries with secondary instrumentation achieve a high stiffness of the screwed up segments. Monocortical expansion screws combined with a trapezoidal plate allow ventral stabilization of the cervical spine that is comparable to the plate fixation using bicortical screws.

Comparison of ventral corpectomy and plate-screw-instrumented fusion with dorsal laminectomy and rod-screw-instrumented fusion for treatment of at least two vertebral-level spondylotic cervical myelopathy

The objective of the article is to verify the hypothesis that the dorsal multilevel laminectomy and rod-screw-instrumented fusion (DLF) for multilevel spondylotic cervical myelopathy (MSCM) is less strenuous for patients, and less prone to perioperative complications, than ventral multilevel corpectomy and plate-screw-instrumented fusion (VCF), while clinical outcome is comparable. One hundred and three successive patients were treated for at least two vertebral-level MSCM, 42 of them by VCF and 61 by DLF. The two patients groups were retrospectively compared. VCF patients were slightly younger than DLF patients (62.5 +/- 10.61 years versus 66 +/- 12.4 years, P = 0.012). In VCF patients, a median of 2 (2-3) corpectomies and in DLF patients a median of 3 (2-5) laminectomies were performed. In VCF patients, surgery lasted longer than in DLF patients (229 +/- 60 min versus 183 +/- 46 min, P < or = 0.001). Between the VCF and the DLF patients groups, no significant difference was found in perioperative complications (e.g. hardware failure rates of 16.7% in VCF and of 6.6% in the DLF patients) and mortality rates. The postoperative outcome, as assessed by the postoperative change of the Nurick scores, the change of neck pain, the patients' satisfaction, and the change of the subaxial Cobb angle of the spine did not differ between the two patients groups. However, when comparing the postoperative Nurick scores directly, VCF patients fared somewhat better than DLF patients [median of 2 (0-5) versus 3 (1-5), P = 0.003]. The hypothesized advantages of DLF over VCF in the surgical treatment of at least two vertebral-level MSCM could not be confirmed in this retrospective study. A prospective randomized study is warranted to clarify this issue.

Biomechanical testing of unstable humeral shaft fracture plating

This study compared the biomechanical performance of 4.5-mm limited-contact dynamic compression plates (DCPs) and 3.5-mm locking compression plates (LCPs) for the fixation of unstable humeral shaft fractures. Composite humeri were divided into two groups: 3.5-mm LCPs and 4.5-mm DCPs. Osteotomy gaps of 5 mm, simulating diaphyseal comminution, were created. Stiffness tests were performed in anterior-posterior (AP) bending, medial-lateral (ML) bending, torsion, and axial compression. Results showed that while construct stiffnesses in ML bending and torsional loading are significantly higher for the 4.5 DCP group (p < .05), no statistically significant differences were observed in AP bending or axial compression. Fatigue characteristics under cyclic AP bending conditions were also evaluated, although no failures occurred. Data from the literature suggest that stiffness results for the LCP constructs perhaps afford sufficient fixation strength capable of supporting the physiologic loads most commonly applied during postoperative rehabilitation. However, results indicate that the DCP construct is mechanically advantageous for stabilizing diaphyseal comminuted fractures.

Complications during and after surgery of the lower cervical spine by isolated anterior approach with CSLP implant

BACKGROUND

The merits of different operative approaches in the management of spinal injury is debated. The aim of this study was to assess, retrospectively, the outcome of treatment of injuries of the lower cervical spine by an anterior approach, in terms of fusion rate and complications.

MATERIALS AND METHODS

Between 1995 and 2004, 270 patients with an injury of the lower cervical spine were operated on by an anterior approach in our hospital. There were 67 females and 203 males. Using the Aebi and Nazarian classification, 22% of patients had a type A injury, 23% of patients had a type B injury and 55% of patients had a type C injury. All had an anterior approach with monocortical stabilisation using a cervical spine locking plate [Synthes].

RESULTS

Radiological evidence of fusion was found in all but one patient at 6 months. Complications occurred in a small proportion of the series. Recurrent laryngeal nerve injury was noted in seven patients, an abscess in the wound in one patient, a haematoma requiring re-operation for evacuation in two patients. The cervical locking plate broke in one patient and this patient went on to develop a pseudoarthrosis from failure to fuse. In another patient there was release of the plate osteosynthesis.

CONCLUSIONS

Treatment of the injured lower cervical spine by an anterior operation and plate fixation was successful in achieving bone fusion in almost every patient and was followed by a complication in only a small proportion of our series. Similar results in other reports indicate that this approach is a safe and effective procedure.