Minimally invasive lateral occipitocervical fixation: case series and technique description.

PURPOSE: Occipitocervical junction (OCJ) instability is commonly treated with fixation via open posterior approach. The use of intraoperative navigation allows us to perform occipitocervical fixation via minimally invasive approach. We report a series of patients treated with percutaneous occipitocervical fixation, describing the surgical procedure in detail and discussing the technique. METHODS: We prospectively enrolled 8 patients affected by OCJ instability secondary to trauma and rheumatoid arthritis. Traumatic patients were preoperatively evaluated with CT scan and MRI scan if needed. Rheumatoid arthritis group was evaluated with both CT and MR. Patients underwent percutaneous occipitocervical fixation with the assist of intraoperative 3D imaging and navigation. All patients were functionally and radiologically evaluated pre-, at 6 weeks, and at 1 year postoperatively. RESULTS: Percutaneous occipitocervical fixation was successfully performed in all of the patients. 33 screws were placed. 29 (87.88%) were placed without any pedicle breach. In 3 (9.09%) screws we observed a minor; and in 1 (3.03%) screw we observed a major pedicle breach. We did not have any postoperative complications. CONCLUSIONS: Described method of occipitocervical fixation is a minimally invasive method that has a similar outcome to the open technique. It requires the experience in open techniques and the assist of intraoperative 3D imaging and navigation to be performed efficiently.

Video-Based Microsurgical Education versus Stationary Basic Microsurgical Course: A Noninferiority Randomized Controlled Study.

BACKGROUND: Repetitive training is essential for microsurgical performance. This study aimed to compare the improvement in basic microsurgical skills using two learning methods: stationary microsurgical course with tutor supervision and self-learning based on digital instructional materials. We hypothesized that video-based training provides noninferior improvement in basic microsurgical skills. METHODS: In this prospective study, 80 participants with no prior microsurgical experience were randomly divided into two groups: the control group, trained under the supervision of a microsurgical tutor, and the intervention group, where knowledge was based on commonly available online instructional videos without tutor supervision. Three blinded expert microsurgeons evaluated the improvement in basic microsurgical skills in both groups. The evaluation included an end-to-end anastomosis test using the Ten-Point Microsurgical Anastomosis Rating Scale (MARS10) and a six-stitch test on a latex glove. Statistically significant differences between groups were identified using standard noninferiority analysis, chi-square, and t-tests. RESULTS: Seventy-seven participants completed the course. Baseline test scores did not differ significantly between groups. After the 4-day microsurgical course, both groups showed statistically significant improvement in microsurgical skills measured using the MARS10. The performed tests showed that data for self-learning using digital resources provides noninferior data for course with surpervision on the initial stage of microsurgical training (7.84; standard deviation [SD], 1.92; 95% confidence interval [CI], 7.25-8.44) to (7.72; SD, 2.09; 95% CI, 7.07-8.36). CONCLUSION: Video-based microsurgical training on its initial step provides noninferior improvement in microsurgical skills to training with a dedicated instructor.

The position and morphometry of the fovea capitis femoris in computed tomography of the hip.

PURPOSE: The position of the fovea of the femoral head is usually considered to be inferior or inferoposterior, despite the fact that few detailed anatomical studies have been performed. This study was performed to assess the position of the fovea in computed tomography and its correlation with standard radiographic measures of the proximal femur. METHODS: Computed tomography scans of the hip of 107 patients (54 women and 53 men) were evaluated. The semi-coronal and transverse views were used to assess the femoral neck-shaft angle and the neck version, as well as the size and position of the fovea in relation with the femoral neck axis and the size of the head. RESULTS: The fovea was always located inferior to the neck axis in the semi-coronal plane. In the transverse plane, the fovea was always slightly posterior to the femoral neck axis, as approximately ¾ of its diameter was posterior to the axis. The position was unrelated to the neck-shaft axis and the neck-trochanter minor angle. There were no differences in the position between men and women; however, in women, the fovea is slightly larger than in men when related to the femoral head size. CONCLUSION: The femoral neck axis in the transverse plane always crosses the anterior aspect of the fovea. Its position is unrelated to the angular geometry of the proximal femur, but related to the femoral head size. It is found to be relatively larger in women.

The prevalence and ossification pattern of the biphalangeal and triphalangeal lateral toes.

PURPOSE: Biphalangealism of the toes is an exclusively human phenomenon. The aim of this study was to evaluate the development of the lateral toes in childhood by following the ossification pattern of the phalanges. METHODS: Foot radiographs of 913 adults have been evaluated for biphalangealism of 3rd to 5th toe. The pediatric group, aged 6-15 years of age, was assessed for the number of ossification centers in the foot. RESULTS: In adults, the mean prevalence of biphalangealism in the 5th toe was 41.39%, in the 4th toe was 2.15%, and in the 3rd toe was 0.48%. In children, 45% feet had four ossification centers in the 5th toe. The epiphysis center of the middle and distal phalanx was missing. In the 4th toe, four centers were present in of 2.47% of cases. Those values are similar to the prevalence of the biphalangeal toes in adult population. The remaining toes had 5 or 6 ossification centers. In the 5-center toe, the epiphysis of the middle phalanx was missing. CONCLUSION: A missing distal phalanx epiphyseal ossification center is considered indicative of a biphalangeal toe, and the toes with 5 or 6 ossification centers are indicative of triphalangeal toes. The reason for such evolution of the lateral toes is still debated, but the differences in anatomy most likely have no impact on foot function.

The sensory function of the uninjured nerve in patients after median and ulnar nerve injury.

STUDY DESIGN: A retrospective cohort study. INTRODUCTION: Some patients after median or ulnar nerve injury report a diminished sensibility in the fingers that are supplied by the uninjured nerve. PURPOSE OF THE STUDY: The purpose of this study was to evaluate the function of the uninjured nerve in patients after peripheral nerve injury to assess the presence and degree of its functional impairment. METHODS: There were 28 patients with median and 29 patients with ulnar nerve injury examined for sensory disturbances in the injured and uninjured nerves, using several tests assessing touch, temperature, and vibration sensibility. RESULTS: In 16 patients after ulnar and 13 patients after median nerve injury, some disturbances in the uninjured nerve were found, mostly in individual tests. Only 8 patients had 3 or more different tests abnormal. DISCUSSION: The injured nerve function in patients with functional disturbances in the uninjured nerve was worse than in patients with normal test results. CONCLUSION: Posttraumatic changes in central nervous system are the possible reasons. LEVEL OF EVIDENCE: Level III study.

The influence of the surgeon's handedness and standing position at the operating table on the radiological outcomes in primary total knee arthroplasty.

BACKGROUND: The purpose of this study was to compare radiological outcomes of total knee arthroplasty (TKA) in mechanical alignment implant positioning in the coronal and sagittal planes depending on surgeons' handedness and their position at the operating table. METHODS: A total number of 200 consecutive patients with idiopathic osteoarthritis and varus knees who underwent TKA were retrospectively included in this research. Patients were operated on by 4 surgeons (50 for each surgeon) selected according to their handedness and position at the operative table. Surgeon I (right-handed, standing at the operating table always on the right side); Surgeon II(left-handed, standing at the operating table always on the left side); Surgeon III (right-handed, standing at the operating table on the side of the operated limb); Surgeon IV (left-handed, standing at the operating table on the side of the operated limb). RESULTS: Comparing postoperative radiological results statistically significant differences were calculated in the case of deviation from HKA angle (left TKA -1.5°; Interquartile Range [IQR] = -2.6-[-1] vs right TKA -3°; IQR = -4.5-[-2]; p = 0.01) for surgeon II and MPTA for surgeon IV (left TKA 0°; IQR = -1-0.5 vs right TKA 1°; IQR = 0-2; p < 0.01). Higher deviation from the mechanical alignment angles and implant positioning was revealed for a less convenient operation site for the surgeon. CONCLUSION: We recommend that all surgeons performing TKAs from the less comfortable side should take great care in establishing the MPTA and HKA angles to avoid surgical errors in implant positioning and limb alignment.

The effectiveness of percutaneous vertebroplasty in the treatment of different aetiology Vertebral Body Fractures.

Percutaneous Vertebroplasty (PV) has gained widespread popularity in the treatment of Vertebral Body Fractures (VBFs). The procedure involves the injection of polymethylmethacrylate (PMMA) cement into the fractured vertebral body via a needle that is placed percutaneously using either a transpedicular or extrapedicular approach. Health Related Quality of Life (HRQoL) evaluation is a widespread method of measure of the disease severity and the outcome of the treatment. The subjective feeling of pain in VBFs is crucial for the HRQoL. The aim of the study was to determine the effectiveness of percutaneous vertebroplasty in the treatment of VBFs. A group of 187 patients with VBFs of different etiology resulting from osteoporosis, trauma or tumors were treated with PV in Pomeranian Center of Traumatology in Gdansk from 2010 to 2011. The effectiveness of the treatment was evaluated with Visual Analog Scale (VAS), Hospital Anxiety and Depression Scale (HADS-M), Rolland Morris Scale (RMS), 36-Item Short Form Health Survey (SF-36) and Oswestry Disability Index (ODI) questionnaires administered before and one month after surgery. PV decreased significantly VAS score, depression and anxiety level, what improved significantly HRQoL in patients with VBFs.

Secondary scoliosis after thoracotomy in patients with aortic coarctation and patent ductus arteriosus.

The aim of this study was to determine the influence of lateral thoracotomy on the development of scoliosis in subjects undergoing repair of coarctation of the aorta (CoAo) and patent ductus arteriosus (PDA). A group of 133 patients with CoAo and PDA was evaluated. Forty-five patients with CoAo and 38 with PDA were operated on using lateral thoracotomy (operative group) while 12 patients with CoAo and 31 with PDA were treated using balloon dilatation and stent or coil implantation (non-operative group). Clinical examination and the evaluation of spinal roentgenograms were performed. Among the operated patients 46.6% of those with CoAo and 39.5% of those with PDA had clinical scoliosis. In the non-operated patients scoliosis was present in only 16.6% of those with CoAo and 12.9% of those with PDA. Scoliosis ranged between 10° and 42° and it was mild in the majority of cases. In 90.4% of the operated scoliotic patients with CoAo and 73.3% of those with PDA the curve was thoracic and in 47.6% of the CoAo group and 53,3% of the PDA group the curve was left sided. All curves were right sided in non-operated subjects. Scoliosis in the operated group was higher in males than in females (63.3% versus 60% in CoAo and 68.2% versus 37.5% in PDA). The prevalence of scoliosis after thoracotomy was significantly higher than after non-surgical methods of treatment of both CoAo and PDA as well as in the general population. The rate of single thoracic and the rate of left thoracic curves in patients after thoracotomy is higher than in patients treated non-surgically or in idiopathic scoliosis. The rate of scoliosis after thoracotomy is higher in males than females especially following thoracotomy for PDA.

Operative treatment of isthmic spondylolisthesis with posterior stabilization and ALIF. Cages versus autogenous bone grafts.

In the following study the use of cages and autogenous bone grafts were compared in the operative treatment of isthmic spondylolisthesis with the posterior stabilization and Anterior Lumbosacral Interbody Fusion (ALIF). 55 patients were divided into two groups. Autogenous bone grafts were used in the first group (34 patients) and titanium interbody implants (cages) in the second group (21 patients). The mean follow up period in the first group was 8.6 years and 3.4 years in the second group. The radiological outcome was based upon the evaluation of the degree of spondylolisthesis, the angle of the lumbar lordosis, the height of the interbody space and intervertebral foramen and the evaluation of the spinal fusion. The objective clinical outcome assessment was based on Oswestry Disability Index. Subjective clinical evaluation was performed with the use of Visual Analog Pain Score (VAS) and the two questions concerning the evaluation of success of the operative treatment and a possible agreement to the following operation if necessary. The use of autogenous bone grafts alone in ALIF was related to the significant loss of achieved segmental spine anatomy restoration. The implantation of the cages prevented the loss of slippage correction, permanently reconstructed the anatomical conditions in the area of the operated spinal segment.

Intraoperative Neurophysiologic Monitoring (INM) in scoliosis surgery.

Even among skilled spinal deformity surgeons, neurologic deficits are inherent potential complications of spine surgery. The aim was to assess the meaning of changes and to evaluate the critical rates of Somatosensory Evoked Potentials (SEP) and Motor Evoked Potentials (MEP) for Neurologic Deficit (ND) occurrence associated with scoliosis surgery. A Group of 30 patients with idiopathic scoliosis treated surgically by posterior correction and stabilisation were included. Patients were matched by age, sex, aetiology, Cobb angle, and surgical criteria. Data on three planar scoliosis correction and concomitant (INM) alarms were compared. Radiographic assessment was performed from radiographs taken before surgery and just after it. The (INM) was performed with the use of ISSIS (Inomed) in every patients the same fashion. The average thoracic curve correction was 69.7% and lumbar 69.8%. The average preoperative Apical Vertebral Rotation was 23.5° for thoracic and 27.9° for lumbar curves and postoperatively 10.9° and 14.3° respectively. There was a significant variability of SEP during surgery with only 7 (23%) patients with stable SEP. 15(50%) patients had a decrease of SEP below 50% and 8(27%) had severe decrease of SEP below 50% what caused us to stop surgery or to decrease correction of curves. There was a MEP decrease in 11(37%) patients and in 6 (20%) directly after correction up to 50% of normal value. In 5 of 30 (17%) patients there was a significant decrease of MEP below 50% and we immediately released the implant. The SEP decrease up to 50% without any MEP change did not influenced the outcome. There was no correlation between flexibility and correction of the curve and SEP and MEP decrease. The safe level for MEP was not determined but its meaning for the outcome was more important than SEP value. The need of (INM) during scoliosis surgery to avoid (ND) was confirmed.

Cerclage cable augmentation does not increase stability of the fixation of intertrochanteric fractures. A biomechanical study.

BACKGROUND: Intertrochanteric fractures with a posteromedial intermediate fragment are unstable because of the loss of medial support. Additional fixation with a cerclage is used in subtrochanteric fractures, but not in intertrochanteric fractures. The aim of this biomechanical study is to evaluate whether cerclage fixation improves stability of intertrochanteric fractures. HYPOTHESIS: Our hypothesis is that the cerclage fixation of the intermediate fragment increases fixation stability of intertrochanteric fractures. MATERIALS AND METHODS: Synthetic femora with intertrochanteric fractures (AO 31.A1.3) with a posteromedial fragment were fixed with a long gamma nail. The intermediate fragment was fixed with a cerclage cable. Four groups were compared: 1: no cable fixation; 2: anatomic reduction and cable fixation; 3: anatomic reduction and fixation of a fragment where its proximal part was removed simulating comminution; 4: non-anatomic reduction and cable fixation. The specimens were loaded axially in a testing machine. The preload was 100N, followed by ten conditioning cycles from 100N to 500N. The test phase consisted of the cyclic loading between 100N and the maximum force that increased at a rate of 50N at each cycle until failure. The stiffness was calculated from the load/displacement curve of the last three conditioning cycles. RESULTS: There were no statistically significant differences between force to failure (group 1: 681N; group 2: 846N; group 3: 699N; group 4: 806N; ANOVA p=0.23) and stiffness (group 1: 769N/mm; group 2: 819N/mm; group 3: 815N/mm; group 4: 810N/mm; ANOVA p=0.84) between groups. There were significant differences in the widening of the lag screw canal (group 1: 2.16mm; group 2: 4.5mm; group 3: 3mm; group 4: 2.5mm; ANOVA p=0.017). In individual comparison, the differences were significant only between the anatomical reduction group and the non-anatomical reduction (p=0.04) and the no cable group (p=0.02). DISCUSSION: There is a controversy in clinical literature whether cable fixation improves treatment outcome of proximal femoral fractures. This study suggests that medial wall reconstruction with a cerclage cable does not improve axial stability of the fixation. LEVEL OF EVIDENCE: Not applicable; a biomechanical study.

Local infiltration analgesia with bupivacaine and adrenaline does not reduce perioperative blood loss in total hip arthroplasty.

This study evaluates the effect of local infiltration analgesia with bupivacaine and adrenaline on perioperative blood loss in total hip arthroplasty. Patients who had primary total hip arthroplasty were retrospectively assigned to two groups. One group had 100 ml of bupivacaine/adrenaline solution injected into periarticular soft tissues at the end of the procedure. There were 55 patients in the infiltrated hip group and 44 patients in the not infiltrated group. Patients' hemoglobin level (Hb), hematocrit (HTC), red blood count (RBC), platelet count (PLT) and International Normalized Ratio (INR) as well as the need for blood transfusions were compared statistically between groups preoperatively and postoperatively. There were no significant differences between Hb, HTC or RBC levels as well as the rate and amount of blood transfusions on the 1st, 4th postoperative days or at patients' discharge between infiltrated and not infiltrated groups. This study does not support the hypothesis that the use of local infiltration analgesia with adrenaline may reduce perioperative blood loss in total hip arthroplasty.

The cement-bone bond is weaker than cement-cement bond in cement-in-cement revision arthroplasty. A comparative biomechanical study.

This study compares the strength of the native bone-cement bond and the old-new cement bond under cyclic loading, using third generation cementing technique, rasping and contamination of the surface of the old cement with biological tissue. The possible advantages of additional drilling of the cement surface is also taken into account. Femoral heads from 21 patients who underwent a total hip arthroplasty performed for hip arthritis were used to prepare bone-cement samples. The following groups of samples were prepared. A bone-cement sample and a composite sample of a 6 weeks old cement part attached to new cement were tested 24 hours after preparation to avoid bone decay. Additionally, a uniform cement sample was prepared as control (6 weeks polymerization time) and 2 groups of cement-cement samples with and without anchoring drill hole on its surface, where the old cement polymerized for 6 weeks before preparing composite samples and then another 6 weeks after preparation. The uniaxial cyclic tension-compression tests were carried out using the Zwick-Roell Z020 testing machine. The uniform cement sample had the highest ultimate force of all specimens (n = 15; Rm = 3149 N). The composite cement sample (n = 15; Rm = 902 N) had higher ultimate force as the bone-cement sample (n = 31; Rm = 284 N; p <0.001). There were no significant differences between composite samples with 24 hours (n = 15; Rm = 902 N) and 6 weeks polymerization periods (n = 22; Rm = 890 N; p = 0.93). The composite cement samples with drill hole (n = 16; Rm = 607 N) were weaker than those without it (n = 22; Rm = 890 N; p < 0.001). This study shows that the bond between the old and new cement was stronger than the bond between cement and bone. This suggests that it is better to leave the cement that is not loosened from the bone and perform cement in cement revision, than compromising bone stock by removal of the old cement with the resulting weaker cement-bone interface. The results support performing cement-in-cement revision arthroplasty The drill holes in the old cement mantle decrease cement binding strength and are not recommended in this type of surgery.

The early failure of the gamma nail and the dynamic hip screw in femurs with a wide medullary canal. A biomechanical study of intertrochanteric fractures.

BACKGROUND: Intertrochanteric fractures may occur in a bone with a wide medullary canal that may lead to significant mobility of a intramedullary nail, contrary to an extramedullary device. This study evaluates the Dynamic Hip Screw and the gamma nail in AO 31.A2.1 fractures in these circumstances. METHODS: Synthetic femora with canals drilled to 18 mm were used. Five fixation types were examined: a 2 - hole and a 4 - hole Dynamic Hip Screw with a 2 - hole plate, a standard gamma nail with dynamic and static distal locking and a long gamma nail. The specimens were tested with cyclic axial loading, from 500 N increasing of 50 N increments in each cycle. Force at failure, overall stiffness, stiffness at the fracture site, location and mode of failure were recorded. FINDINGS: The short gamma nails dislocated into varus under preload because the nail migrated laterally. The Dynamic Hip Screw was initially stable, but some specimens rotated around the lag screw. The gamma nail was rotationally stable. Both implants failed through femur fracture. The long gamma nailed failed by screw cut - out at forces lower than the ultimate force of the short gamma nail. INTERPRETATION: This study shows that the gamma nail is unstable in a large medullary canal but offers better rotational stability of the proximal fragment. A modification of the nail design or the operative technique may be considered.

Drill holes decrease cancellous bone strength: A comparative study of 33 paired osteoporotic human and 9 paired artificial bone samples.

This study was designed to compare compressive strength of cancellous bone retrieved from the femoral head in a specimen with and without guide wire hole, with comparison to synthetic bone samples. Femoral heads retrieved from 33 patients who sustained femoral neck fractures and underwent hip arthroplasty were cut into cuboids leaving two matching samples from the same femoral head. Similar samples were prepared from synthetic femurs. One of the matching samples was chosen at random and was drilled with a guide wire for cancellous screws. The uniaxial compression tests of bone blocks were carried out using the Zwick-Roell Z020 strength testing machine. The mean loss of sample cross section area due to drilling was 24%. The force at failure in drilled specimens was significantly smaller by 18% in human (median: 26%) and by 25% in synthetic bone (median 27%). The strength of human specimens was almost 2 times greater, and their stiffness nearly 4 times greater than in synthetic samples. The study shows that the weakening of the bone after drilling is roughly proportional to the loss of sample cross section area. The percentage decrease in strength was similar in human and artificial bone, but human samples were stronger and stiffer. The comparison shows that forces measured in biomechanical studies on artificial bone cannot be directly attributed to humans, but the relative differences in mechanical properties of synthetic samples after some damage may be accurate and resemble that of human bones.

Scoliosis in patients with aortic coarctation and patent ductus arteriosus: does standard posterolateral thoracotomy play a role in the development of the lateral curve of the spine?

The aim of this study was to determine the influence of lateral thoracotomy on the development of scoliosis in subjects undergoing repair of coarctation of the aorta (CoA) and patent ductus arteriosus (PDA). A group of 133 patients with CoA and PDA was evaluated. Forty-five patients with CoA and 38 with PDA underwent surgery using standard posterolateral thoracotomy (operative group), whereas 12 patients with CoA and 31 with PDA were treated using balloon dilatation and stent or coil implantation (nonoperative group). A spinal examination, together with the evaluation of chest and spinal roentgenograms, was conducted. Among the operated patients, 62% of those with CoA and 55% of those with PDA had clinical scoliosis. In the nonoperated patients, scoliosis was present in only 25% of those with CoA and 16% of those with PDA. Scoliosis ranged between 10 degrees and 42 degrees . In 89% of the operated patients with CoA and 76% of those with PDA the curve was thoracic; in 46% of the CoA group and 57% of the PDA group the curve was left-sided. All curves were right-sided in nonoperated subjects. Scoliosis in the operated group was higher in male than in female subjects (63% vs. 60% in CoA and 86% vs. 37% in PDA). The prevalence of scoliosis after standard posterolateral thoracotomy was significantly higher than after nonsurgical treatment methods in the CoA and PDA groups as well as in the general population. The rate of single thoracic and the rate of left-sided thoracic curves in patients after thoracotomy is higher than in nonoperated patients or in those with idiopathic scoliosis. The rate of scoliosis after thoracotomy is higher in male than female patients, especially after thoracotomy for PDA.

Possible causes of failure in treatment of forearm bone shaft fractures - own experience.

BACKGROUND: Non-surgical treatment of forearm shaft fractures in adults is associated with a high incidence of non-union. Operator errors during surgery also often result in bone union complications. We attempted to identify the errors made during the treatment or other factors that might influence the development of forearm shaft union complications. MATERIALS AND METHODS: We have analysed the causes of 67 cases of non-union in 53 patients (17 women and 36 men), aged 18 to 85 years. Thirty-five patients were treated by open repositioning and fixation with plates and screws, 11 patients were treated by closed or open reposition and stabilization with Kirschner wires, and 4 patients had closed reposition and immobilization in a plaster cast. Other methods were used in 3 patients. RESULTS: In the group treated by open reposition and plate fixation, we found the following complications that might impede bone union: plate fracture, technical errors, screw loosening, bone inflammation, and other complications. In the group treated by closed or open repositioning and stabilization with Kirschner wires, we found the following factors that might impede bone union: open fractures, inaccurate fracture repositioning and inappropriately inserted Kirschner wires. CONCLUSIONS: Using rigid fixation, for example with a plate and screws, and avoidance of technical errors seem to be the most appropriate measures helping to decrease the risk of non-union during treatment of a fracture of both forearm shafts.

Cadaveric biomechanical testing of torque - to - failure magnitude of Bilateral Apical Vertebral Derotation maneuver in the thoracic spine.

It remains unclear what is the real safe limit of torque magnitude during Bilateral Apical Vertebral Derotation (BAVD) in thoracic curve correction. Up to author's knowledge there is no study except this one, to reproduce in-vivo real measurements and intraoperative conditions during BAVD maneuver. The objective of this study was to evaluate the torsional strength of the instrumented thoracic spine under axial rotation moment as well as to define safety limits under BAVD corrective maneuver in scoliosis surgery. 10 fresh, full-length, young and intact human cadavers were tested. After proper assembly of the apparatus, the torque was applied through its apical part, simulating thoracic curve derotation. During each experiment the torque magnitude and angular range of derotation were evaluated. For more accurate analysis after every experiment the examined section of the spine was resected from the cadaver and evaluated morphologically and with a CT scan. The average torque to failure during BAVD simulation was 73,3 ± 5,49Nm. The average angle of BAVD to failure was 44,5 ± 8,16°. The majority of failures were in apical area. There was no significant difference between the fracture occurrence of left or right side of lateral wall of the pedicle. There was no spinal canal breach and/or medial wall failure in any specimen. The safety limits of thoracic spine and efficacy of BAVD for axial plane correction in the treatment of Adolescent Idiopathic Scoliosis (AIS) were established. It provided qualitative and quantitative information essential for the spinal derotation under safe loading limits.

A comparison of the effect of autogenous vs. frozen homogenous grafts on the healing of non-union of forearm bones.

BACKGROUND: A large percentage of autogenous and homogenous grafts are resorbed and replaced by the recipient's own tissue. It is generally believed that autogenous grafts are superior to homogenous ones. The aim of our study was to compare the effectiveness of autografts and allografts in achieving the healing of a non-union of forearm bones. MATERIAL AND METHODS: Between 1976 and 2005, 56 patients with 68 non-unions of forearm bone shafts were operated on. The study group consisted of 45 male and 11 female patients aged 8 to 85. The patients were operated on using methods requiring autogenous cancellous bone chips or homogenous frozen grafts. Autografts were used in 47 patients, and allografts were applied in the treatment of 21 non-unions. The effectiveness and speed of achieving a bone union with both types of grafts were subsequently compared. RESULTS: The percentage and time of bone union were similar between autogenous and homogenous grafts. The differences are not statistically significant. CONCLUSION: No statistically significant differences in the effectiveness and time to bone union were found between recipients of autogenous vs. homogenous grafts. The use of homogenous frozen grafts seems justified when the mechanical advantages of the graft are not essential. It also allows for avoiding additional mutilation to healthy parts of the body.

Direct Vertebral Rotation Versus Single Concave Rod Rotation: Low-dose Intraoperative Computed Tomography Evaluation of Spine Derotation in Adolescent Idiopathic Scoliosis Surgery.

STUDY DESIGN: A comparative clinical study of two main corrective manoeuvres in scoliosis surgery. OBJECTIVE: To compare the effectiveness of two main corrective manoeuvres: single concave rod rotation (SCRR) and direct vertebral rotation (DVR) in regard to apical vertebral rotation (AVR) and rib hump correction in adolescent idiopathic scoliosis (AIS) surgery. SUMMARY OF BACKGROUND DATA: It remains unclear whether SCRR manoeuvre alone causes apical vertebral derotation (AVD) and rib hump correction. Although the influence of DVR on AVD and rib hump change has been described, it has been evaluated mainly with indirect methods. This is the first study to evaluate separately the derotational effectiveness of these two manoeuvres during the low-dose intraoperative computed tomography (ICT). METHODS: A study group consisted of 38 AIS patients treated by posterior scoliosis surgery (PSS) with all pedicle screw constructs. All examined patients had dow-dose ICT evaluation (before correction, after SCRR, and after DVR). RESULTS: We found SCRR ineffective - mean postcorrectional AVR increased insignificantly 1.5° (16.1% worsening) P = 0.170. On the contrary, an average postcorrectional AVR after DVR decreased significantly mean 3.1° (33.3% improvement) P = 0.049. Precorrectional rib hump angle was 19.3°, after SCRR 15°, and after DVR 12.3°. It was found that despite the lack of true derotation after SCRR there was a significant 22.3% decrease of the rib hump P = 0.043. Although the rib hump decreased significantly 36.3% after DVR as well P = 0.023. There was also significant difference between a rib hump angle after SCRR and DVR (P = 0.049). CONCLUSION: SCRR does not lead to AVD. The true spinal derotation is possible only when DVR systems are used. The decrease of rib hump is achieved after both SCRR and DVR, but the improvement is significantly better after DVR. LEVEL OF EVIDENCE: 3.