Expandable titanium cages for anterior column cervical reconstruction and their effect on sagittal profile: a review of 48 cases

Background

Expandable cervical cages have been utilised successfully to reconstruct the cervical spine for various conditions. However, to date there are only limited data on their influence on cervical sagittal profile. In this retrospective study, we present our experience with performing anterior cervical corpectomy in one or two levels using expandable titanium cages in order to achieve stable reconstruction and restoration of cervical lordosis.

Methods

A case series of data from 48 consecutive patients (20 men, 28 women; mean age 61 years) operated upon in a 5-year-period is retrospectively reviewed. Standard anterior single- or two-level cervical corpectomy, fusion and spinal reconstruction were performed, including placement of an expandable titanium cage and an anterior cervical plate. The mean follow-up was 23 months (range, 8–42 months). Outcome was measured by clinical examinations and visual analogue scale (VAS) scale; myelopathy was classified according the Nurick grading system. Radiographic analysis comprised several parameters, including segmental Cobb angle, cervical lordosis, subsidence ratio and sagittal cage angle. Computed tomography was done 1 and 2 years after surgery; cervical spine radiographs were obtained 3, 6, 12 and 24 months after surgery.

Results

In 38 patients (79 %) osseous fusion or stability of construct could be demonstrated in the 2-year follow up examination. The mean restoration of segmental Cobb angle as well as cervical lordosis amounted to 7.6° and 5.4° respectively, both being statistically significant. Furthermore, a profound correction (10° or more) of the sagittal cervical curve was shown in 15 patients.

Conclusion

Regarding the restoration of the physiological sagittal cervical profile, expandable cervical cages seem to be efficient and easy to use for cervical spine reconstruction after anterior corpectomy. Donor-site-related complications are avoided, fast and strong reconstruction of the anterior column is provided, resulting in satisfactory fusion rates after 2 years.     

Comparison of fusion rates following transforaminal lumbar interbody fusion using polyetheretherketone cages or titanium cages with transpedicular instrumentation

Purpose

Compared to titanium cage, polyetheretherketone (PEEK) cage with pedicle screw fixation has been increasingly used in transforaminal lumbar interbody fusion (TLIF). However, there is insufficient evidence supporting the superiority of PEEK cages over titanium cages as optimal TLIF spacers. The aim of this study was to compare the clinical and radiographic outcomes of patients at a 2-year follow-up after undergoing instrumented TLIF in which either a PEEK cage or a titanium cage was implanted.

Materials and methods

We retrospectively analyzed prospectively collected 48 patients who underwent single-level TLIF in which the first 23 patients received a titanium cage and the 25 patients received a PEEK cage. Patient demographics, clinical outcomes, and radiographic imaging were studied.

Results

Improvement of clinical outcomes was comparable between the two groups. Based on the criteria using computed tomography, 96 % in the Titanium group and 64 % in the PEEK group showed fusion at 12 months. At 24 months, fusion rate in the Titanium group was increased to 100 %, while PEEK group showed 76 % of fusion rate. In the PEEK group, vertebral osteolysis was noted in 60 % of the cases with nonunion. This abnormal finding was not observed in the Titanium group. Vertebral osteolysis was significantly associated with nonunion.

Conclusions

The superiority of PEEK cages over titanium cages for bony fusion was not demonstrated. Additionally, we found unfavorable radiographic findings in the cases with a PEEK cage, which may lead to nonunion. Improvement in biocompatibility of a PEEK cage will be needed to increase the fusion rate.     

Anterior corpectomy and fusion to C2 for cervical myelopathy: clinical results and complications

Purpose

Anterior cervical corpectomy and fusion (ACCF) to C2 (ACCF-C2) for multilevel lesions is a challenging procedure that is indicated for massive ossification of the posterior longitudinal ligament (OPLL) extending to C2 or stenosis at the upper cervical region accompanied by kyphosis. However, there is little information on the effectiveness of and complications related to ACCF-C2. The purpose of this study was to investigate the overall surgical results and postoperative complications of ACCF-C2 for cervical myelopathy.

Methods

Sixteen patients who underwent ACCF-C2 for OPLL and cervical spondylotic myelopathy were evaluated. An iliac bone or a fibular strut was grafted using a cervical plate. The mean fusion level was 3.8, and the mean follow-up period was 36 months. Patients’ charts, clinical results assessed using the Japanese Orthopedic Association (JOA) scale, and radiographs were retrospectively reviewed.

Results

The average preoperative JOA score was 11.5 ± 3.5, and improved significantly to 13.1 ± 3.2 at 24 months after surgery (P < 0.01). The postoperative cervical alignment was significantly improved at the last follow-up (P < 0.05). Seven patients experienced complications, including neurological complications in three, graft-related complications in three, cerebrospinal fluid leakage in two, late retropharyngeal perforation in one, and dysphasia in one. Three of 16 patients experienced upper airway obstruction in this series, and 2 of 473 patients who underwent anterior cervical decompression and fusion at lower levels in the same period (P < 0.001).

Conclusions

ACCF-C2 is effective for massive OPLL and stenosis accompanied by kyphosis. To avoid complications, skilled decompression and bone grafting technique are necessary, and delayed extubation for upper airway obstruction is preferable.     

Evaluation of a new type of titanium mesh cage versus the traditional titanium mesh cage for single-level, anterior cervical corpectomy and fusion

Study design

A retrospective review of prospectively collected data in an academic institution.

Objective

To evaluate the safety and efficacy of a new type of titanium mesh cage (TMC) in single-level, anterior cervical corpectomy and fusion (ACCF).

Methods

Fifty-eight patients consecutive with cervical spondylotic myelopathy (CSM) from cervical degenerative spondylosis and isolated ossification of the posterior longitudinal ligament were treated with a single-level ACCF using either a new type of TMC (28 patients, group A) or the traditional TMC (30 patients, group B). We evaluated the patients for TMC subsidence, cervical lordosis (C2–C7 Cobb and Cobb of fused segments) and fusion status for a minimum of 30 months postoperatively based on spine radiographs. In addition, neurologic outcomes were evaluated using the Japanese Orthopedic Association (JOA) scores. Neck pain was evaluated using a 10-point visual analog scale (VAS).

Results

The loss of height of the fused segments was less for group A than for group B (0.8 ± 0.3 vs. 2.8 ± 0.4 mm) (p < 0.01); also, there was a lower rate of severe subsidence (≥3 mm) in group A (4 %, 1/28) than in group B (17 %, 5/30) (p < 0.01). There were no differences in the C2–C7 Cobb and Cobb of fused segments between the groups preoperatively or at final follow-up (p > 0.05), but the Cobb of fused segments immediately postoperative were significantly less for group B than for group A (p < 0.01). All patients, however, had successful fusion (100 %, each). Both groups had marked improvement in the JOA score after operation (p < 0.01), with no significant differences in the JOA recovery ratio (p > 0.05). The postoperative VAS neck pain scores for group A were significantly less than that for group B (p < 0.05); severe subsidence was correlated with neck pain.

Conclusions

The new type of TMC provides comparable clinical results and fusion rates with the traditional TMC for patients undergoing single-level corpectomy. The new design TMC decreases postoperative subsidence (compared to the traditional TMC); the unique design of the new type of TMC matches the vertebral endplate morphology which appears to decrease the severity of subsidence-related neck pain in follow-up.     

Sacropelvic fixation versus fusion to the sacrum for spondylodesis in multilevel degenerative spine disease

Study design

Retrospective study.

Objective

For successful multilevel correction and stabilization of degenerative spinal deformities, a rigid basal construct to the sacrum is indispensable. The primary objective of this study was to compare the results of two different sacropelvic fixation techniques to conventional stabilization to the sacrum in patients with multilevel degenerative spine disease.

Methods

A total of 69 patients with multisegmental fusion surgery (mean number of stabilized functional spinal units: 7.0 ± 3.3) with a minimum of 1-year follow-up were included. 32 patients received fixation to the sacrum (S1), 23 patients received S1 and iliac screw fixation (iliac) and 14 patients were treated with iliosacral plate fixation (plate). Primary outcome parameters were radiographic outcome concerning fusion in the segment L5–S1, rate of screw loosening, back and buttock pain reduction [numeric rating scale for pain evaluation: 0 indicating no pain, 10 indicating the worst pain], overall extent of disability after surgery (Oswestry Disability Index) and the number of complications.

Results

The three groups did not differ in body mass index, ASA score, the number of stabilized functional spinal units, duration of surgery, the number of previous spine surgeries, or postoperative complication rate. The incidence of L5–S1 pseudarthrosis after 1 year in the S1, iliac, and plate groups was 19, 0, and 29 %, respectively (p < 0.05 iliac vs. plate). The incidence of screw loosening after 1 year in the S1, iliac, and plate groups was 22, 4, and 43 %, respectively (p < 0.05 iliac vs. plate). Average Oswestry scores after 1 year in the S1, iliac, and plate groups were 40 ± 18, 42 ± 20, and 58 ± 18, respectively (p < 0.05 both S1 and iliac vs. plate).

Conclusion

The surgical treatment of multilevel degenerative spine disease carries a significant risk for pseudarthrosis and screw loosening, mandating a rigid sacropelvic fixation. The use of an iliosacral plate resulted in an inferior surgical and clinical outcome when compared to iliac screws.     

The addition of epidural local anesthetic to systemic multimodal analgesia following lumbar spinal fusion: a randomized controlled trial

Purpose

This randomized trial aimed to evaluate the effects of adding continuous epidural analgesia with a bupivacaine and hydromorphone solution to systemic multimodal analgesia following one- or two-level lumbar spinal fusion.

Methods

Thirty-nine patients undergoing lumbar spinal fusion, stratified for sex and one- or two-level fusion, were randomized to receive a continuous postoperative epidural infusion of either 0.1% bupivacaine with 15 μg·mL^?1 hydromorphone (LA group) or 0.9% saline (NS group) at 6 mL·hr^?1 for 48 hr through an epidural catheter placed intraoperatively. All patients received a standardized postoperative multimodal analgesia regimen. Patients, healthcare providers, and research staff were blinded. The primary outcome measure was cumulative opioid consumption (oral morphine equivalent) during the first 48 hr postoperatively.

Results

The mean (SD) cumulative opioid consumption 48 hours postoperatively was 249.3 (143.3) mg in the NS group and 184.7 (208.1) mg in the LA group (mean difference 64.6 mg; 95% confidence interval ?54.3 to 183.5; P = 0.27). There were no adverse events in either group.

Conclusion

Continuous epidural infusion combined with systemic multimodal analgesia resulted in a mean reduction in 48-hr cumulative opioid consumption of 64.6 mg (95% confidence interval ?54.3 to 183.5) following one- or two-level lumbar spinal fusion. This estimate of effect is imprecise, and the routine use of continuous epidural analgesia in this surgical population is not yet warranted. This trial was registered at www.clinicaltrials.gov: NCT00644111.     

The dynamic locking screw (DLS) can increase interfragmentary motion on the near cortex of locked plating constructs by reducing the axial stiffness

Background

The plate–screw interface of an angular stable plate osteosynthesis is very rigid. So far, all attempts to decrease the stiffness of locked plating construct, e.g. the bridged plate technique, decrease primarily the bending stiffness. Thus, the interfragmentary motion increases only on the far cortical side by bending the plate. To solve this problem, the dynamic locking screw (DLS) was developed.

Materials and methods

Comparison tests were performed with locking screws (LS) and DLS. Axial stiffness, bending stiffness and interfragmentary motion were compared. For measurements, we used a simplified transverse fracture model, consisting of POM C and an 11-hole LCP3.5 with a fracture gap of 3 mm. Three-dimensional fracture motion was detected using an optical measurement device (PONTOS 5 M/GOM) consisting of two CCD cameras (2,448?×?2,048 pixel) observing passive markers.

Results

The DLS reduced the axial stiffness by approximately 16% while increasing the interfragmentary motion at the near cortical side significantly from 282 µm (LS) to 423 µm (DLS) applying an axial load of 150 N.

Conclusion

The use of DLS reduces the stiffness of the plate–screw interface and thus increases the interfragmentary motion at the near cortical side without altering the advantages of angular stability and the strength.     

Which posterior instrumentation is better for two-level anterior lumbar interbody fusion: translaminar facet screw or pedicle screw?

Purpose

To determine whether translaminar facet screws can provide stability equivalent to pedicle screws and whether the two posterior instrumentations have the same influence on the adjacent segments in two-level anterior lumbar interbody fusion.

Methods

In a biomechanical study conducted, we used 12 fresh human lumbar spines and tested an intact spine with a stand-alone two-level anterior lumbar interbody fusion and anterior fusion augmented with pedicle screws or translaminar facet screws, under 400 N compressive preloads and 7.5 N m moments in flexion, extension, axial rotation and lateral bending, and measured the stiffness of the operated level, range of motion and intradiscal pressure at the adjacent levels.

Results

We found a significant increase in the stiffness of the segments operated, range of motion and intradiscal pressure at the adjacent superior segment in the stand-alone two-level anterior lumbar interbody fusion during flexion, axial rotation and lateral bending, but a decrease in extension, when compared with the intact spine. The stiffness of operated segments, range of motion and intradiscal pressure in the adjacent segment are significantly higher in the two-level anterior lumbar interbody fusion augmented with posterior instrumentation than in the stand-alone two-level anterior lumbar interbody fusion. There was no significant difference between the two augmented constructs except that, at the adjacent superior segment, the intradiscal pressure was more in the construction augmented with a pedicle screw than with a translaminar facet screw in flexion.

Conclusions

Translaminar facet screws can provide stability equivalent to pedicle screws, but their influence on the adjacent segments is relatively lower; therefore, we suggest that translaminar facet screws be the choice in the optimal posterior instrumentation in a two-level anterior lumbar interbody fusion.     

Differences between arthroplasty and anterior cervical fusion in two-level cervical degenerative disc disease

Purpose

Although arthroplasty is an accepted option for two-level disease, there is a paucity of data regarding outcomes of two-level cervical arthroplasty. The current study was designed to determine differences between two-level cervical arthroplasty and anterior fusion.

Methods

Seventy-seven consecutive patients who underwent two-level anterior cervical operations for degenerative disc disease were divided into the arthroplasty (37 patients) and fusion (40 patients) groups. Clinical outcomes were measured by Visual Analogue Scale (VAS) of neck and arm pain, Japanese Orthopedic Association (JOA) scores, and Neck Disability Index (NDI). Every patient was evaluated by radiography and computed tomography for fusion or detection of heterotopic ossification.

Results

Thirty-seven patients (with 74 levels of Bryan discs) were compared with 40 patients who had two-level anterior fusion (mean follow-up of 39.6 ± 6.7 months). There was no difference in sex, but the mean age of the arthroplasty group was significantly younger (52.1 ± 9.1 vs. 63.0 ± 10.6 years, p < 0.001). The mean estimated blood loss was similar (p = 0.135), but the mean operation time was longer in the arthroplasty group (315.5 ± 82.0 versus 224.9 ± 61.8 min, p < 0.001). At 24 months post-operation, the arthroplasty group had increased their range of motion than pre-operation (23.5° versus 20.1°, p = 0.018). There were significant improvements in neck or arm VAS, JOA scores, and NDI in both groups. However, there were no differences in clinical outcomes or adverse events between the two groups.

Conclusions

Clinical outcomes of two-level arthroplasty and anterior cervical fusion are similar 39.6 months after surgery. Cervical arthroplasty preserves mobility at the index levels without increased adverse effects.     

A biomechanical comparison of fixed angle locking compression plate osteosynthesis and cement augmented screw osteosynthesis in the management of intra articular calcaneal fractures

Purpose

The purpose of this study was to investigate whether cement-augmented screw osteosynthesis results in stability comparable to conventional fixed-angle locking plate osteosynthesis using cadaveric bones to model a Sanders type 2B fracture.

Methods

Seven pairs of fresh frozen human calcanei and the corresponding tali were used. The specimens were assigned pairwise to two study groups in a randomised manner. In order to determine the initial quasi-static stiffness of the bone-implant construct, testing commenced with quasi-static compression ramp loading; subsequently, sinusoidal cyclic compression loading at 2 Hz was performed until construct failure occurred. Initial dynamic stiffness (cycle 1), range of motion (ROM), cycles to failure and load to failure were determined from the machine data during the cyclic test. In addition, at 250-cycle intervals, Böhler’s angle and the critical angle of Gissane were determined on mediolateral X-rays shot with a triggered C-arm; 5° angle flattening was arbitrarily defined as a failure criterion.

Results

Bone mineral density was normally distributed without significant differences between the groups. The augmented screw osteosynthesis resulted in higher stiffness values compared to the fixed-angle locking plate osteosynthesis. The fracture fragment motion in the locking plate group was significantly higher compared to the group with augmented screw osteosynthesis.

Conclusions

The results of this study indicate that in our selected test set-up augmented screw osteosynthesis was significantly superior to the conventional fixed-angle locking plate osteosynthesis with respect to primary stability and ROM during cyclic testing.     

Mehrsegmentale interkorporelle Fusion vs. Wirbelkörperersatz

Background

The surgical techniques of interbody fusion and vertebral body replacement represent two concurrent options for multilevel anterior decompression and arthrodesis of the cervical spine.

Patients and methods

In a retrospective study the data from 61 patients who received either interbody fusion (n?=?38) as anterior cervical discectomy and fusion (ACDF) or vertebral body replacement (n?=?23) (as anterior cervical corpectomy and fusion (ACCF) because of degenerative disc disease of the cervical spine were collected.

Results

The clinical outcome was better at all time points in the patient group with ACDF than in those with ACCF but with no statistically significant differences. The operated segments showed a more rapid fusion progress after ACDF during the time course in comparison to ACCF; however, there was no relationship between the grade of fusion and the clinical result.

Conclusion

In direct comparison multisegmental interbody fusion showed better results with respect to the clinical outcome and bony fusion with a lower rate of complications than vertebral body replacement. However, the differences did not reach statistical significance.     

Periprothetische Femurfrakturen

Background

Due to the increasing age of patients and the rising number of joint replacements, the incidence of periprosthetic fractures (PPF) is also increasing. The treatment should be selected with knowledge of the prefracture interface status and the type of fracture involved. The aim of this study was to evaluate our treatment of PPF with long-term follow-up.

Patients and methods

From 1988 to 2006, 99 patients with PPF were treated in our department. In 86 cases a plate osteosynthesis was used. After a mean time of 7.3±2.8 years, we studied 56 patients and monitored their complications.

Results

The most diagnosed fracture was Johansson type III (44%). Seventy-one patients were treated with a conventional and 15 with locking-plate osteosynthesis. In 15 cases (17.5%) we found severe complications (3 breaks and 3 dislocations of the plates, 6 cases of pseudarthrosis, 2 deep wound infections, and 1 case of postoperative bleeding).

Conclusion

Due to the minor frequency of severe complications, plate osteosynthesis of a periprosthetic fracture with a loosened interface is a good therapeutic option for individual patients, particularly for geriatric patients and those without disorders specific to a loosened interface.     

Radiographic and clinical assessment on the accuracy and complications of C1 anterior lateral mass and C2 anterior pedicle screw placement in the TARP-III procedure: a study of 106 patients

Purpose

To investigate the (1) radiographic and clinical accuracy of C1 anterior lateral mass screw (C1ALMS) and C2 anterior pedicle screw (C2APS) placement in the transoral atlantoaxial reduction plate (TARP)-III procedure, (2) screw insertion-associated clinical complications and (3) fusion status between C1 and C2.

Methods

Radiographic and clinical data were obtained from the electronic medical record system. Studies were carried out to assess the accuracy of C1ALMS and C2APS placement, the screw insertion-associated clinical complications and the fusion status between C1 and C2. Placement of the screws was assessed using the modified All India Institute of Medical Sciences outcome-based classification.

Results

Two-hundred and twelve C1ALMS and 207 C2APS in 106 patients were assessed. The ideal accurate rates were 92.0 % (195) and 53.1 % (110), and the acceptable accurate rates were 97.6 % (207) and 87.0 % (180), respectively. One patient died postoperatively due to C2 screw misplacement. There were no symptoms of neurologic and vertebral artery injuries in the rest of the patients. 102 patients (97.1 %) achieved solid fusion between C1 and C2. No instrumentation failure due to delayed union or nonunion was observed.

Conclusion

C1ALMS placement in TARP-III procedures appears to be safe. The cortical breach rate of C2APS is high though clinically the neurovascular complication rate is similar to that of posterior atlantoaxial procedures. Advanced navigation strategies may help improve the accuracy of C2APS placement and decrease potential complications.     

Clinical outcomes of unstable thoracolumbar junction burst fractures: combined posterior short-segment correction followed by thoracoscopic corpectomy and fusion

Background

There is significant controversy surrounding the ideal management of thoracolumbar burst fractures. While several treatment and management algorithms have been proposed, the ideal treatment strategy for these fractures remains unsettled. The authors review their experience with short-segment posterior fusion followed by anterior thoracoscopic corpectomy for the treatment of unstable thoracolumbar burst fractures.

Methods

We identified all patients treated by a single surgeon at our institution from 2002 to 2009 with short-segment posterior fusion followed by anterior thoracoscopic corpectomy for unstable thoracolumbar junction burst fractures. Demographic data, mechanism of injury, classification of fracture, Cobb angle, American Spinal Injury Association score, associated injuries, tobacco use, follow-up duration, and radiographic studies were all collected. Outcomes were assessed for fracture alignment (preoperative, postoperative, and long-term follow-up kyphosis), rate of fusion, neurological outcome, and treatment complications.

Results

Thirty-two patients with burst fracture of the thoracolumbar junction defined as T10 to L1 were included. At a mean follow-up of 20.4 months, 90 % of patients had demonstrated radiographic evidence of fusion and 91 % retained the correction of their kyphotic deformity. There were three complications in the series.

Conclusions

Short-segment posterior fusion with thoracoscopic anterior corpectomy represents an alternative to traditional open treatment of thoracolumbar burst fractures. A thoracoscopic approach allows for a short-segment posterior fusion, reducing the loss of adjacent motion segments, minimizes morbidity associated with traditional open anterior approaches, allows for anterior and posterior column stabilization, and is associated with a high rate of bony fusion.     

Comparative effectiveness of PEEK rods versus titanium alloy rods in lumbar fusion: A preliminary report

Background

Posterior lumbar instruments made of titanium and its alloys could change the physiological distribution of load at the instrumented and adjacent segments, which is a main cause of implant failure, non-fusion and adjacent segment degeneration. Posterior lumbar rods made of polyetheretherketone (PEEK) which is a semirigid alternative to titanium and its alloys have been introduced in lumbar fusion. This prospective study compared the radiological and clinical outcomes of patients undergoing lumbar fusion with PEEK rods versus titanium alloy rods.

Methods

Using transpedicular fixation and lumbar fusion, 21 patients were treated with titanium alloy rods (TI group), and 20 patients with PEEK rods (PEEK group). Radiological and clinical outcomes were evaluated, including the status of the implanted instruments, fusion rate, lumbar lordosis angle (LA), disc space height (DH), visual analog score (VAS) for lower back pain (VAS-BP) and leg pain (VAS-LP), Japanese Orthopedic Association scoring system (JOA score) and complications.

Results

Clinical VAS-BP, VAS-LP and JOA scores were significantly improved at 3 months, 6 months, and 1 year postoperatively as compared with preoperative scores in both groups (p?<?0.05), with similar levels of improvement observed at the same time points postoperatively between the two groups. The overall fusion rate was 100 % at the 1-year follow-up for both groups. No significant differences in lumbar lordosis angle were found preoperatively, 1 week and 1 year postoperatively in both groups (p?>?0.05). The postoperative increase of disc space height and loss of disc space height during the follow-up showed a similar extent of change between both groups (p?>?0.05).

Conclusions

PEEK rods offer a similar radiological and clinical efficacy as titanium alloy rods. PEEK rods, as a semirigid implant with unique characteristics, may be an effective alternative treatment for patients with degenerative lumbar disease in lumbar fusion.     

Anterior surgical options for the treatment of cervical spondylotic myelopathy in a long-term follow-up study

Objective

To provide a basis for the choice of anterior surgery procedures in the treatment of cervical spondylotic myelopathy (CSM) through long-term follow-up.

Methods

A consecutive series of 89 patients with CSM having complete follow-up data were analyzed retrospectively. All patients were treated with anterior cervical discectomy and fusion (ACDF), and anterior cervical corpectomy and fusion (ACCF) from July 2000 to June 2007. The lesions were located in one segment (n = 25), two segments (n = 56), and three segments (n = 8). Preoperative and postoperative, the C2–C7 angle, cervical intervertebral height, radiographic fusion status, result of the adjacent segment degeneration, the Japanese Orthopaedic Association (JOA), and the Short Form 36-item (SF36) questionnaire scores were used to evaluate the efficacy of the surgery.

Results

According to the different compression conditions of the 89 cases, different anterior operation procedures were chosen and satisfactory results were achieved, indicating that direct anterior decompressions were thorough and effective. The follow-up period was 60–108 months, and the average was 79.6 months. The 5-year average symptom improvement rate, effectiveness rate, and fineness rate were 78.36 %, 100 % (89/89), and 86.52 % (77/89), respectively.

Conclusions

For CSM with compression coming from the front side, proper anterior decompression based on the specific conditions could directly eliminate the compression. Through long-term follow-up, the effect of decompression became observable.     

„Impingement“ der posterolateralen Humerusplatte

Background

Double-plate osteosynthesis has to be considered the gold standard for treating complex distal humeral fractures in adults. Impingement of the posterolateral plate with the olecranon or the radial head in extension of the elbow joint is a possible complication after double-plate osteosynthesis with a 90° configuration, especially after olecranon osteotomy.

Objectives

The goal of this study was to analyze the positioning of the posterolateral humeral plate in order to define guidance values for intraoperative application.

Methods

The positioning of the posterolateral humeral plate in relation to the olecranon in full extension of the elbow joint was analyzed in 71 dissected upper extremities of cadavers. Values on the cadavers were measured under image-intensifier control (distal olecranon impingement line) that can be reproduced intraoperatively.

Results

The average distance between the distal edge of the plate and junction of cartilage and bone at the capitulum humeri was 4.8 mm (SD?±?1.2 mm). The average distances from the medial border of the plate to the lateral border of the olecranon fossa and to the lateral epicondyle were 2.5 mm (SD?±?0.9 mm) and 22.7 mm (SD?±?2.4 mm), respectively. The distal olecranon impingement line averaged 5.2 mm (SD?±?1.5 mm) on the left and 7.2 mm (SD?±?1.4 mm) on the right side of cadavers.

Conclusions

The measured values offer landmarks for correct positioning of the posterolateral humeral plate. The distance between the lateral border of the olecranon fossa and the medial edge of the posterolateral plate as well as the proximal end of the distal olecranon impingement line should be respected in order to avoid impingement. If possible, the posterolateral plate should be placed at least 4.3 mm lateral to the radial edge of the olecranon fossa so that impingement can be successfully avoided.     

Are Quadrilateral Surface Buttress Plates Comparable to Traditional Forms of Transverse Acetabular Fracture Fixation?

Background

Several construct options exist for transverse acetabular fracture fixation. Accepted techniques use a combination of column plates and lag screws. Quadrilateral surface buttress plates have been introduced as potential fixation options, but as a result of their novelty, biomechanical data regarding their stabilizing effects are nonexistent. Therefore, we aimed to determine if this fixation method confers similar stability to traditional forms of fixation.

Questions/purposes

We biomechanically compared two acetabular fixation plates with quadrilateral surface buttressing with traditional forms of fixation using lag screws and column plates.

Methods

Thirty-five synthetic hemipelves with a transverse transtectal acetabular fracture were allocated to one of five groups: anterior column plate + posterior column lag screw, posterior column plate + anterior column lag screw, anterior and posterior column lag screws only, infrapectineal plate + anterior column plate, and suprapectineal plate alone. Specimens were loaded for 1500 cycles up to 2.5x body weight and stiffness was calculated. Thereafter, constructs were destructively loaded and failure loads were recorded.

Results

After 1500 cycles, final stiffness was not different with the numbers available between the infrapectineal (568 ± 43 N/mm) and suprapectineal groups (602 ± 87 N/mm, p = 0.988). Both quadrilateral plates were significantly stiffer than the posterior column buttress plate with supplemental lag screw fixation group (311 ± 99 N/mm, p < 0.006). No difference in stiffness was identified with the numbers available between the quadrilateral surface plating groups and the lag screw group (423 ± 219 N/mm, p > 0.223). The infrapectineal group failed at the highest loads (5.4 ± 0.6 kN) and this was significant relative to the suprapectineal (4.4 ± 0.3 kN; p = 0.023), lag screw (2.9 ± 0.8 kN; p < 0.001), and anterior buttress plate with posterior column lag screw (4.0 ± 0.6 kN; p = 0.001) groups.

Conclusions

Quadrilateral surface buttress plates spanning the posterior and anterior columns are biomechanically comparable and, in some cases, superior to traditional forms of fixation in this synthetic hemipelvis model.

Clinical Relevance

Quadrilateral surface buttress plates may present a viable alternative for the treatment of transtectal transverse acetabular fractures. Clinical studies are required to fully define the use of this new form of fixation for such fractures when accessed through the anterior intrapelvic approach.     

Alterations in axial curvature of the cervical spine with a combination of rotation and extension in the conventional anterior cervical approach

Purpose

Alterations of three-dimensional cervical curvature in conventional anterior cervical approach position are not well understood. The purpose of this study was to evaluate alignment changes of the cervical spine in the position. In addition, simulated corpectomy was evaluated with regard to sufficiency of decompression and perforation of the vertebral artery canal.

Methods

Fifty patients with cervical spinal disorders participated. Cervical CT scanning was performed in the neutral and supine position (N-position) and in extension and right rotation simulating the conventional anterior approach position (ER-position). Rotation at each vertebral level was measured. With simulation of anterior corpectomy in a vertical direction with a width of 17 mm, decompression width at the posterior wall of the vertebrae and the distance from each foramen of the vertebral artery (VA) were measured.

Results

In the ER-position, the cervical spine was rotated rightward by 37.2° ± 6.2° between the occipital bone and C7. While the cervical spine was mainly rotated at C1/2, the subaxial vertebrae were also rotated by several degrees. Due to the subaxial rotation, the simulated corpectomy resulted in smaller decompression width on the left side and came closer to the VA canal on the right side.

Conclusions

In the ER-position, the degrees of right rotation of subaxial vertebrae were small but significant. Therefore, preoperative understanding of this alteration of cervical alignment is essential for performing safe and sufficient anterior corpectomy of the cervical spine.     

Two-level pedicle subtraction osteotomy for severe thoracolumbar kyphotic deformity in ankylosing spondylitis

Study design

A retrospective clinical study.

Objective

To evaluate the outcomes of two-level (T12 and L3) pedicle subtraction osteotomy (PSO) for severe thoracolumbar kyphosis in ankylosing spondylitis (AS), and to discuss the surgical strategies of this surgery.

Background

Cases were limited on the results of two-level PSO for correction of severe kyphosis caused by AS, nor on surgical strategies of this type of surgery.

Methods

From March 2006 to December 2010, nine consecutive AS patients with severe kyphotic deformity, underwent T12 and L3 PSOs. Chin-brow vertical angle (CBVA) and radiographic assessments which contain thoracic kyphosis (TK), lumbar lordosis (LL), global kyphosis (GK), and sagittal vertical axis were carefully recorded pre and postoperatively to evaluate the sagittal balance. Intra and postoperative complications were also registered. All patients were asked to fill out Oswestry Disability Index before surgery and at the last follow-up visit.

Results

All nine patients (8M/1F), averaged 41.4 years old (range 35–51 years), were received two-level (T12 and L3) PSO, and were followed up after surgery for a mean of 39.9 months (range 24–68 months). Good cosmetic results were achieved in all patients. Mean correction at two-level PSO was 67.9 ± 5.5°. All CBVA, TK, LL, and GK were changed significantly after surgery (P < 0.05), the mean amount of correction of which were 59.5 ± 13.8, 34.7 ± 3.8, 33.2 ± 2.4, and 54.0 ± 14.8 degrees, respectively, and with a small loss of correction at the last follow-up visit. Sagittal imbalance was significantly improved from 27.3 ± 4.4 to 3.4 ± 0.7 cm postoperatively. Neither mortalities nor any major neurological complications were found. The mean ODI score was significantly improved from 53.4 ± 15.5 before surgery to 8.2 ± 4.7 at the last visit.

Conclusion

The outcomes of follow-up showed that two-level (T12 and L3) PSO can effectively and safely correct severe thoracolumbar kyphosis in AS.