Objective:To investigate the feasibility and safety of posterior atlantooccipital joint-occipital condyle-clivus screw fixation.Methods:Twelve fresh frozen cadaveric skull specimens containing complete upper cervical spine were collected.Under direct vision, 2.0 mm diameter Kirschner wires were implanted into the specimens through the atlantooccipital joint-occipital condyle-clivus, followed by X-ray imaging and the measurement of head tilting and leaning angle of the Kirschner wire trajectory.CT scan was performed to observe whether Kirschner wires passed through the atlantooccipital joint, whether they were in the clivus, whether they broke the medial wall of the atlas and the lateral wall of the occipital condyle, and whether they invaded the hypoglossal canal, vertebral foramina, and sphenoid sinus.The specimens were dissected to primarily observe whether the lateral atlas and the medial and lateral bones of the occipital condyle were damaged, whether Kirschner wires invaded the hypoglossal canal, and whether Kirschner wires broke through the bones on both sides and upper part of the clivus.The Kirschner wires were withdrawn and an electronic caliper was employed to measure the distance of Kirschner wire trajectory in the bone tissues.Results:The leaning angle and head tilting angle of the Kirschner wire trajectory of the 12 specimens were 20.29°±3.10° and 53.51°±4.61°,and the distance of trajectory was（52.03±1.02）mm.There was no significant difference in the leaning angle and head tilting angle, as well as distance of left and right trajectories（20.23°±3.35° vs 20.34°±2.98°,t=-0.523,P=0.611;53.45°±4.64° vs 53.57°±4.79°,t=-0.496,P=0.630;51.93±1.15 vs 52.12±0.92 mm, t=-1.161,P=0.270）.As revealed by CT scan, all Kirschner wires passed through the atlantooccipital joint and were in the clivus, without penetrating the medial wall of the atlas and the lateral wall of the occipital condyle, and without invading the hypoglossal canal, vertebral foramina, and sphenoid sinus.The anatomical results of the specimens showed that lateral atlas and the medial and lateral bones of the occipital condyle were not damaged, and Kirschner wires did not invade the hypoglossal canal or break through the bones on both sides and the upper part of the clivus. Conclusion:The posterior atlantooccipital joint-occipital condyle-clivus screw fixation technique is feasible and safe in anatomy and imaging,and can be used as a supplement to posterior occipitocervical fusion.

目的:评估寰椎椎弓根螺钉联合经寰枢关节螺钉固定技术的力学稳定性.方法:选取成人颈椎新鲜标本6具,解剖剔除肌肉制备上颈椎完整模型(完整组),用生物力学测试及计算机视觉分析软件测量在1.5Nm力矩下前屈后伸、左右侧弯和左右旋转时C 1-C2的活动度(ROM);破坏寰椎前弓和侧块制备不稳模型(失稳组),再次测量相同力矩下各运动方向C1-C2的ROM活动度.随后暴露寰枢椎置钉点,根据先后顺序置入寰椎椎弓根螺钉+枢椎椎弓根螺钉固定(C1P+C2P组)、单纯经寰枢关节螺钉固定(TA组)、寰椎椎弓根螺钉+经寰枢关节螺钉固定(C1P+TA组),依次分别测量相同力矩下各运动方向C1-C2的ROM,比较各组C1-C2 ROM的差异.结果:失稳组相较于完整组在六个方向上有更大的ROM,两组所有方向上的ROM均有显著性差异(P＜0.05);C1P+C2P组、C1P+TA组、TA组与失稳组比较,所有方向上的ROM均有显著性减少(P＜0.05),三组间比较,前屈、后伸、左旋转和右旋转方向上的ROM存在统计学差异(P＜0.05),C1P+TA组＜C1P+C2P组＜TA组;左侧弯和右侧弯方向上的ROM无统计学差异.结论:三种固定技术均可达到良好的固定效果,在侧弯时的稳定性相似,C1P+TA固定在屈伸和旋转稳定性方面更好,在严重寰椎爆裂骨折时可以考虑采用该固定方式.

Objective:To investigate the anatomical safety and feasibility ofposterior occipitocervical fixation with atlan-tooccipital-clivus screw.Methods:Data of 60 patients who treated in the spinal department of our hospital with upper cervical computed tomographic scans from February 2017 to November 2019 were retrospectively collected. Occipitocervical infection, injury, tumor and deformity were excluded. The Mimics software was used to reconstruct the occiput, atlas and measure the anatomical parameters, including the height and width of the anterior edge of the clivus, the height and width of the middle part of the clivus, the thinnest distance of the soft tissue in front of the clivus, the anteroposterior diameter, transverse diameter, the angle of inside tilting in coronary plane of the occipital condyle, the distance from the hypoglossal canal to the atlantooccipital articular surface, the anteroposterior diameter and transverse diameter of the superior joint of atlas, the height of the lateral mass, and the height and transverse diameter of the inferior articular process of the superior atlas joint. The three-dimensional digital modeling was performed and the screw diameter of 3.5mm was simulated. 3-Matic software were used to measure the screw placement parameters, including the inside tilting angle in coronary plane of screw, and the angle of upper tilting in sagittal plane and length of screw. The atlanto-occipital junction was exposed at the rear of 8 cadavers. According to the above parameters, the titanium alloy screws with a diameter of 3.5 mm were transferred from the inferior articular process and posterior arch of the atlas to the clivus through the atlantooccipital. Finally, the screw path was cut along the nail path with a pendulum saw, and the track of the screw was observed to confirm the safety and effectiveness of the screw.Results:The leading edge height and width of male clivus was 16.8±2.5 mm and 20.1±3.1 mm. The middle part of the clivus was 9.7±2.3 mm and 22.4±3.7 mm. The thinnest soft tissue in front of the clivus was 5.8±1.48 mm. The anteroposterior diameter of the occipital condyle was 19.1±1.9 mm, the transverse diameter was 12.6±2.0 mm, the inside tilting angle was 33.7°±4.5°, and the vertical distance from the lowest point of the neural tube to the articular surface of the occipital condyle was 9.6±1.1 mm. The height of the lateral mass of atlas was 12.9±2.4 mm, the anteroposterior diameter of the upper joint of atlas was 21.7±1.9 mm, and the transverse diameter was 11.7±1.4 mm. The width of the inferior facet was 14.9±1.4 mm and the height of the inferior facet was 5.7±0.85 mm. The distance from the screw entry point to the vertical line of the lateral mass migration midpoint was 2.5±0.6 mm; The distance from the screw entry point to the horizontal line of the midpoint was 2.3±0.7 mm.The inside titling angle of screw was 18.4°±1.6°, the upper tilting angle was 55.6°±3.1°, the length of the screw track was 53.0±2.8 mm, the adjustment range of upper tilting angle was 15.0±2.8 mm, the adjustment range of inside tilting angle was 10.4±2.4 mm. The anatomical parameters of females were slightly smaller than those of males, and the difference was statistically significant, but there was no significant difference between left and right parameters. The screws of 8 specimens could be inserted safely and effectively.Conclusion:Atlan-tooccipital-clivus screw can be implanted without damaging the nerve and vascular structure, and it can be used as a choice for occipitocervical fixation.

Objective:To explore the difference in properties of anterior occipital condyle plate screws compared with common anterior occipitalcervical fusion internal fixation.Methods:A 28-year-old healthy adult male volunteer's CT data of the occiput and neck was selected to establish finite element models：including the normal model，simple artificial vertebral fixation model（special-shaped titanium cage+clival screws），anterior occipital condyle plate and screw fixation model，and clival plate and screw fixation model，then a 50 N gravity and a torque of 1.5 N m were exerted upon the upper surface of the occipital bone to make the model produce flexion and extension，lateral bending and rotation. The motion range，internal fixation stress distribution and occipital bone stress distribution of each model under varying conditions were compared.Results:Under the conditions of flexion，extension，lateral bending and rotation，the range of motion of the normal model was 18.65°，15.35°，9.82° and 34.68°，respectively；that of the simple artificial vertebral fixation model was 3.20°，3.63°，2.94° and 3.92°，respectively；that of the clival plate and screw fixation model was 0.40°，0.50°，0.35° and 0.89°，respectively；that of the anterior occipital condylar plate and screw fixation model was 0.27°，0.33°，0.13° and 0.30°，respectively. Compared with the simple artificial vertebral fixation model，the range of motion of the clival plate and screw fixation model decreased by 87.5%，86.2%，88.1% and 77.3% in flexion，extension，lateral bending and rotation. The range of motion of the anterior occipital condylar plate and screw fixation model decreased by 91.5%，90.1%，95.6% and 92.3%，respectively. Under the conditions of flexion and extension，lateral bending and rotation，the stress peak of the simple artificial vertebral fixation model was 52.3 MPa，51.9 MPa，52.6 MPa，respectively；that of the clival plate and screw fixation was 100.1 MPa，158.1 MPa，170.6 MPa，respectively；that of the anterior occipital condylar plate and screw fixation was 114.2 MPa，62.9 MPa，132.9 MPa，respectively. Under the condition of flexion and extension，lateral bending and rotation，the stress peak of the occipital bone in the simple artificial vertebral body internal fixation model was 52.9 MPa，50.9 MPa and 62.3 MPa，respectively；that of the clival plate and screw fixation model was 19.7 MPa，55.9 MPa and 38.3 MPa，respectively；that of the anterior occipital condylar plate and screw fixation model was 37.8 MPa，15.0 MPa and 16.3 MPa，respectively. The stress in bone near the hypoglossal canal was close to 0 MPa，much smaller than the stress peak in occipital bone.Conclusion:Anterior occipital condylar plate and screw fixation in front of the special-shaped titanium cage can improve the stability of occipitocervical fusion with little effect on the occipital bone and hypoglossal canal or without obvious stress concentration，and hence is a safe and reliable anterior fixation method for upper cervical spine instability.

Objective: To analyze the feasibility of anterior occipitocervical fusion biomechanical characteristic of craniovertebral reconstruction by anterior occipital condyle screw plate system. Methods: Six cervical vertebra specimens including 4 males and 2 females were enrolled, whose mean age of death was (49.3±7.5) years. The normal models were established by soft tissue dissection, and the instability models were established by destroy bone and ligament structure including, anterior arch of the atlas, part of the lateral mass of the atlas, the odontoid process, the odontoid apical ligament, the pterygoid ligament, the transverse ligament of the atlas the joint capsule. The clivus screw fixation models were established by anterior clivus screw fixation, and then those models were performed by anterior occipital condyle screw fixation. All four groups were loaded with a 1.5 N·m continuous pure force in flexion-extension, lateral bending, and axial rotation. Then measured the range of motion of specimen C0-C1 and C0-C2. And the pull-out force test was conducted to compare the effects of unicortical and bicortical fixation on the pull-out force of screws. Results: In the C0-C1 segment, the range of motion in flexion-extension (forward and posterior), lateral bending and axial rotation in the clivus group was 6.46°±0.85°, 5.14°±0.76°, 2.73°±0.36°, 1.12°±0.41°, respectively; and it was 5.92°±0.90°, 4.16°±1.06°, 2.86°±0.50°, 1.05°±0.27°, respectively in the occipital condyle group. As for C0-C2 segment, the range of motion in the clivus group was 9.55°±1.99°, 10.46°±2.03°, 6.90°±1.29°, 13.51°±1.37°, respectively; and it was 8.14°±1.38°, 9.53°±1.55°, 4.75°±1.06°, 7.90°±1.68°, respectively, in the occipital condyle group. The ranges of motion in the occipital condyle group were significantly lower than clivus group (all P<0.05). The maximum pull out force by bicortical fixation was significantly better than unicortical fixation ((439±33) N vs (408±28) N, P<0.05). Conclusion: The anterior occipital condyle screw plate system provides better stability especially in anti-bending and anti-rotation than the anterior clival screw fixation.

Objective:To provide a theoretical basis for the clinical application of the posterior route through atlas occipital articular slope screw internal fixation system through the biomechanical study.Methods:Eight cadavers of healthy adults aged 35-60 years and 155-180 cm in height were selected. The specimens with complete anatomical structure and without surgical operation were established as normal models. The model of occipito-atlantoaxial complex was established by breaking the articular capsule, ligament and other connecting structures and cutting the dentate process. The device was established as an internal fixation model through the specimen of atlantooccipital joint slope screw internal fixation system. Given normal model and internal fixation of 1.5 N·m in the moment of flexion, lateral bending and axial rotation and to measure the specimen C 0-C 1 and C 0-C 2 segment of the range (range of motion, ROM), comparative analysis of pillow neck area within the normal model and fixed model changes the range of movement, after the evaluation through the slope between atlas and the occipital screw internal fixation system of mechanical properties. Results:In the normal model, the flexion, flexion and extension, lateral bend and axial rotation ranges of C 0-C 1 segments were 23.85°±2.43°, 4.74°±0.55°, 5.77°±0.75°, respectively; the corresponding activity ranges of C 0-C 2 segments were 30.66°±3.05°, 9.09°±1.37°, 70.97°±9.48°, respectively; in the internal fixation model, the flexion and extension, lateral bend and axial rotation ranges of C 0-C 1 segments were 0.71°±0.24°, 0.24°±0.06°, 0.34°±0.09°, respectively. The corresponding activity range of C 0-C 2 segment was 3.09°±0.82°, 0.74°±0.07°, 1.22°±0.10°, respectively. Compared with the normal model, the range of activity of the internal fixation model in all directions was significantly reduced (<3°), and the reduction ratio of activity was more than 90%. Conclusion:The posterior route through pillow slope screw internal fixation system can effectively reduce the range of motion of the occipital neck in flexion, extension, lateral bending and rotation, and has safe and reliable biomechanical stability.

Objective:To investigate the screw placement parameters, feasibility and safety of posterior atlantooccipital joint-occipital condyle-clivus screw technique in Chinese people.Methods:Upper cervical spine CT images of 46 patients, including 24 males and 22 females, were collected with random number table from June 2019 to May 2020 in Ningbo No.6 Hospital. The patients aged 20-55 years, with a mean age of (39±9) years. Total of 92 sides of upper cervical spine models were obtained by Mimics 19.0 digital three-dimensional reconstruction, and screw placement was conducted simulately. The midpoint of transition zone between the posterior arch of atlas and the inferior articular process of lateral mass was selected as the screw entry point. The diameter and length of screws was 3.5 mm and 50 mm, respectively. Detailed morphometric measurements of the 92 atlantooccipital joint-occipital condyle-clivus screws were conducted. The distance between the screw and its surrounding important structures, screw inside and upper tilting angles, the length of screw trajectory in atlas and the length of screw trajectory on occipital side (occipital condyle-clivus) were all measured. Paired t test was performed on the parameters of left and right screw placement to confirm whether there was difference between the two sides. Results:In the 46 cases of upper cervical spine digital three-dimensional models, 92 posterior atlantooccipital joint-occipital condyle-clivus screws were implanted. All the screws were completely fixed in the clivus, without breaking through the upper sphenoid sinus, entering into the canalis spinalis and foramen magnum, and damaging the surrounding structures such as hypoglossal canal. The screw trajectory parameters between the left and right sides were slightly different, but there was no statistical differences between the two sides ( P>0.05). The vertical distance between the screw entry point and the upper edge of atlas was (12.6±1.0) mm, the vertical distance between the screw entry point and the lower edge of atlas was (6.5±0.6) mm, the distance between the screw and the medial border of atlas vertebral artery foramen was (6.7±0.6) mm, the distance between the screw entry point and the medial wall of atlas was (6.6±0.7) mm, the distance between the screw outer margin and the hypoglossal canal was (5.5±0.6) mm, screw inside tilting angle was 21.2°±2.5°, screw upper tilting angle was 52.0°±3.4°, the length of screw trajectory in atlas was (12.1±0.9) mm, the length of screw trajectory on occipital side (occipital condyle-clivus) was (37.9±0.9) mm. Conclusion:The posterior atlantooccipital joint-occipital condyle-clivus screw technique can serve as a feasible and safe treatment for instability of the occipitocervical junction, which can be used as a new posterior occipitocervical fusion technique.

Objective:To investigate the safety of posterior atlantoaxial transarticular screw combined with atlas pedicle screw fixation in Chinese.Methods:CT data of upper cervical spine in 48 patients were collected from Ningbo No.6 Hospital, including 26 males and 22 females aged 26-58 years [(37.3±13.5)years]. All CT data was transformed into 3D dimensional model and inserted with virtual screws by Mimics 19.0. Firstly, the vertical plane P 1 and the horizontal plane P 2 of the atlas were built in those atlantoaxial models, secondly the atlantoaxial transarticular screw S 0 was inserted by Margel method, and it's insertion point was located at 3 mm lateral and 2 mm cephalad in the C 2 inferior articular process. Finally, four atlas pedicle screws were inserted at the midline of atlas lateral mass. The four screws are inserted as follows. S 1: the screw was tangent to the lateral side of the S 0 or the medial of the atlas pedicle. S 2: the screw was tangent to the lateral wall of the atlas pedicle. S 3: the screw was tangent to the upper wall of the atlas pedicle. S 4: the screw was tangent to the inferior wall of the atlas pedicle. The angles between S 1, S 2 and P 1 as the camber angle, and the angle between S 3, S 4 and P 2 as the gantry angle were measured. Then the safety range of camber angle and gantry angle were calculated, and the screw length of S 1, S 2, S 3 and S 4 was measured. In all models, the camber angle and gantry angle of the screws were adjusted an interval of 2°, the number of successful cases was calculated and the success rate of insertion was calculated. Results:All 3D models were inserted successfully. The minimum value, maximum value and safety range of the camber angle of atlas pedicle screws were (-6.7±5.2)°, (10.4± 4.3)°, (17.1±3.7)°, respectively; and of the gantry angle were (-0.5±3.5)°, (11.0±5.8)°, (11.5±4.9)°, respectively. The length of screw placement was S 1: (31.1±2.4)mm, S 2: (28.3±2.5)mm, S 3: (29.2±3.8)mm, S 4: (29.6±3.0)mm, respectively ( P<0.05). When the camber angle was from -1°to 5°, the success rate of screw placement was 87.5%; when inserting with 2° camber angle, the success rate was 100%; when the gantry angle was 5°, the success rate was 93.8%. Conclusion:The posterior atlantoaxial transarticular screw combined with atlas pedicle screw can achieve satisfy insertion length and success rate.

Background: Extracorporeal shock wave therapy (ESWT) is a nonsurgical treatment for plantar fasciitis (PF) that has had satisfactory clinical outcomes. However, local corticosteroid injection (LCI) is often regarded as first-line treatment of PF, but there have been few studies comparing the 2 methods. Therefore, we compared the effect of ESWT and LCI on patients with PF. Methods: This was a block randomized controlled study comparing 49 patients treated with ESWT and 47 patients treated with LCI from January 2017 to December 2018 who were followed for 6 months. We evaluated the clinical outcomes in the 2 groups, including average pain, first-step pain, plantar fascia thickness, and Foot Function Index, Chinese version of the PF patients. Results: All patients had pain relief and function improvement after treatment, whereas the LCI group did not maintain significant clinical improvement at the 3-month follow-up. The patients in the ESWT group had a significantly better clinical outcome with better duration of improvement than the LCI group. Conclusion: For PF patients, both ESWT and LCI resulted in clinical improvement but EWST provided longer relief than LCI. Level of Evidence: Level II, prospective comparative study.

Objective To compare the clinical efficacy of posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft or iliac bone graft for atlantoaxial instability.Methods A retrospective case-control study was conducted to analyze the clinical data of 56 patients with atlantoaxial instability admitted to the Sixth Hospital of Ningbo from September 2014 to October 2016.There were 35 males and 21 females,with the age range from 9 to 59 years [(50.3 ±3.2) years].A total of 26 patients were treated with posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft (complex group),while 30 patients were treated with iliac bone graft (ilium group).Patients showed different degrees of neck pain and limited neck activity preoperatively.X-ray films and three-dimensional CT examination of the cervical spine were taken before and after operation for evaluating the atlantoaxial reduction,bone graft fusion and internal fixation.The operation time,intraoperative bleeding,bone fusion time,visual analogue scale (VAS),Japanese Orthopaedic Association (JOA) score,atlantodental interval (ADI) and axial symptoms were compared between the two groups,and the complications were recorded.Results Both groups were followed up for 24-30 months,with an average of 27.4 months.In the complex group and the ilium group,the operation time was (2.21 ±0.25) hours and (2.72 ±0.26) hours (P ＜0.01);the intraoperative blood loss was (227.3 ± 45.4) ml and (277.7 ± 43.4) ml,respectively (P ＜ 0.05);the bone fusion time was (6.9 ±0.5) months and (8.1 ± 1.8) months (P ＞ 0.05),respectively.In the complex group,the VAS was (5.45 ± 0.69)points before operation,(2.64 ± 0.51)points at the follow-up one month after operation,(0.91 ± 0.7) points at the follow-up 12 months after operation,and (0.45 ± 0.16) points at the follow-up 24 months after operation;and in the ilium group,the VAS was (5.18 ± 0.75) points,(2.45 ± 0.52)points,(1.27 ± 0.19) points and (0.41 ± 0.18) points correspondingly.In terms of VAS,there were significant differences before and after operation within each group (P ＜ 0.01),while there were no significant differences between the two groups at different time points (P ＞ 0.05).In the complex group,the JOA score was (10.82 ± 0.35) points before operation,(12.73 ± 0.65) points at the follow-up one month after operation,(15.18 ±0.61) points at the follow-up 12 months after operation,and (15.64 ±0.15) points at the follow-up 24 months after operation;and in the ilium group,the JOA score was (10.73 ± 1.19) points,(13.01 ± 0.63) points,(14.73 ± 0.91) points and (15.55 ± 0.51) points correspondingly.In terms of JOA score,there were significant differences between before and after operation within each group (P ＜ 0.01),while there were no significant differences between the two groups at different time points (P ＞ 0.05).In the complex group,the ADI was (2.28 ± 0.59) mm before operation,(1.83 ± 0.56)mm at the follow-up one month after operation,(1.71 ± 0.56)mm at the follow-up 12 months after operation,and (1.59 ± 0.67)mm at the follow-up 24 months after operation;and in the ilium group,the ADI was (2.23 ± 0.60) mm,(1.80 ± 0.18) mm,(1.67 ± 0.69) mm and (1.62 ± 0.53) mm correspondingly.In terms of ADI,there were significant differences between before and after operation within each group (P ＜ 0.01),while there were no significant differences between the two groups at different time points (P ＞ 0.05).The axial symptom scores were graded as excellent in 23 patients and good in three patients of the complex group while excellent in 21 patients and good in nine patients in the ilium group (P ＞ 0.05).There were no patients with spinal nerve injury caused by pedicle screw placement after operation.One patient in the ilium group had incision errhysis and recovered after dressing change,and other patients had no incision infection.Conclusions For atlantoaxial instability,posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft or autogenous iliac bone graft can both achieve satisfactory clinical results.The spinous process-muscle-vascellum complex graft has less operation time and intraoperative bleeding than the autogenous iliac bone graft,which can be a feasible alternative operation.

Objective To compare the clinical and radiological outcome between the modified Broström repair with augmentation using suture tape (MBA) and the modified Broström repair (MB) for patients with chronic lateral ankle instability. Methods A retrospective study was performed in Ningbo No. 6 Hospital. The study included 53 patients who underwent surgical treatment from March 2014 to July 2016 and were followed for 2 years. A total of 25 patients underwent modified Broström repair with augmentation using suture tape, and 28 patients were treated with modified Broström repair. Patients were evaluated using the American Orthopedic Foot and Ankle Scale (AOFAS) hindfoot scale, the Foot and Ankle Ability Measure (FAAM) score, range of motion (ROM), and the visual analogue scale (VAS). The talar tilt angle (TTA) and anterior talar translation (ATT) were used to evaluate the mechanical stability. All radiological outcomes were measured by two orthopaedic surgeons, with the measurements repeated 3 days later. Results The mean age of the patients was 26.6 ± 17.8 years in the MBA group and 28.1 ± 19.4 years in the MB group, and no statistical difference in preoperative data was found between two groups. There were significant differences before and after the operation within the groups. Both groups achieved satisfactory outcomes, and significant improvements (VAS, FAAM, AOFAS, TTA, and ATT) were observed between the 1‐year follow‐up and final follow‐up ( P < 0.05). The MBA group showed significant improvement in the FAAM Sport (87.1 ± 5.4 vs 78.2 ± 12.0, P = 0.001) and total scores (93.1 ± 2.3 vs 90.5 ± 5.1, P = 0.027) at the final follow‐up compared with the MB group, and for the other outcomes, there were no significant differences between the two groups. Conclusion The modified Broström repair with augmentation using suture tap for chronic lateral ankle instability achieves a better outcome; however, further research is necessary.