Computed tomography morphometric analysis of C2 translaminar screw fixation of Wright’s technique and a modified technique in the pediatric cervical spine

Purpose

To establish reference data on the dimensions of C2 lamina to guide the use of translaminar screws with Wright’s technique and a modified technique for pediatric patients in different age groups.

Methods

113 pediatric patients were divided into six age groups, and their cervical vertebrae were studied on CT scans. Laminar height, width, length and screw angle were measured. Statistical analysis was performed using Student t tests, Pearson’s correlation and linear regression analysis.

Results

Mean laminar height was 10.95 ± 2.81 mm, and mean width was 6.01 ± 0.90 mm. For Wright’s technique, mean laminar length was 30.65 ± 3 mm, and the screw angle was 56.02° ± 3.62°. For the modified technique, mean laminar length was 22.07 ± 2.38 mm, and the screw angle was 67.40° ± 3.39°. 95.6 % (108/113) of the children could insert a screw into the lamina (laminar width ≥4.5 mm), 72.6 % (82/113) could accept bilateral translaminar screws (laminar width ≥4.5 mm and laminar height ≥9 mm).

Conclusion

Our investigation provides insight into the anatomy of C2 lamina in six pediatric age groups. Compared to adults, the benefits of C2 translaminar screws fixation are more obvious in the pediatric spine which has a large C2 lamina. Compared to Wright’s technique, the modified technique should insert a screw with bigger insert angle and shorter screw length.     

Operative Therapie bei skapholunären Bandverletzungen

Background

The purpose of this work was to retrospectively evaluate clinical and radiological results after surgical treatment for scapholunate ligament ruptures.

Materials and methods

Measurements of range of motion, strength, and angles, as well as postoperative score assessments were performed in 32 patients.

Results

The average mobility in the operated wrist was 52° for flexion, extension 57°, radial 24°, ulnar deviation 31° and forearm rotation outward 88° and inward 89°. The recovery of force was 89?% compared with the healthy hand. It showed an average skapholunar angle of 63°, a radioulnar angle of 22° and an average carpal height according to Nattrass of 1.49. Our patients rated the operation result with a median DASH score of 11 points (range 0–70.8 points). The median objective Mayo Wrist Score was 80 points (range 45–100 points).

Conclusion

Surgical treatment of scapholunate ligament rupture, especially against the background of carpal collapse, is a very satisfactory method with very good results in the objective function and strength, and a high level of patient satisfaction.     

Remodelling of femoral head–neck junction in slipped capital femoral epiphysis: a multicentre study

Purpose

We examined the remodelling of the femoral head–neck junction in patients with slipped capital femoral epiphysis (SCFE) and the frequency of residual cam deformities.

Methods

We reviewed 69 hips in 56 patients with stable SCFE who had undergone in situ pinning. Mean age at slip was 11.7 years and the follow-up period 63.4 months. Cam deformity was evaluated using the anterior offset alpha (α) angle and head–neck offset ratio (HNOR).

Results

The average α angle and HNOR significantly improved from 76.2° to 51.3° and 0.086 to 0.135, respectively; 25 hips (36.2 %) still had an α angle greater than 50°, and 32 hips (46.4 %) had an HNOR of under 0.145. A multivariate analysis selected age at onset and slip angle as risk factors for cam deformity, with cutoff values 11.1 years and 21.0°, respectively.

Conclusions

Although most hips had remodelling of the head–neck junction, 29.4 % had residual cam deformities that may be susceptible to femoroacetabular impingement.     

Ultrasound evidence of the optimal wrist position for radial artery cannulation

Purpose

Radial artery cannulation is a common medical procedure for anesthesia and critical care. To establish the ideal wrist position for radial artery cannulation, we performed ultrasound examinations of the radial artery to investigate the effect of the angle of wrist extension on radial artery dimensions.

Clinical features

Measurements were performed in 17 healthy subjects and 17 surgical patients scheduled for coronary artery bypass graft (CABG) surgery. The radial artery was echographically visualized near the styloid process of the radius at the wrist. Radial artery dimensions were measured at wrist joint angles of 0, 15, 30, 45, 60 and 75°.

Observations

In both groups, radial artery height was affected by the wrist joint angle. Vessel height was decreased at 60° (one way ANOVA P = 0.027 vs 0°) and 75° (P < 0.001 vs 0, 15, 45°) in healthy subject and at 75° in CABG patients (P < 0.001 vs 0°). The mean differences in radial artery height at 0 and 75° were 0.33 ± 0.09 mm and 0.20 ± 0.06 mm for healthy and CABG patients, respectively. Vessel width was not affected by wrist joint angulation up to 75° of extension.

Conclusion

Our results demonstrate that in healthy subjects, radial artery dimensions are unaltered when the wrist joint is extended up to an angle of 45°. Extension at 60° for healthy subjects and 75° for CABG patients, however, results in a decrease in the height of the radial artery, which could possibly render arterial catheterization more difficult.     

Free-hand placement of occipital condyle screws: a cadaveric study

Purpose

Cranio-vertebral junction fixation is challenging due to the complex topographical anatomy and the presence of important anatomical structures. There are several limitations to the traditional occipital squama fixation methods. The purpose of this work is to assess the safety and feasibility of a new optimum trajectory of occipital condyle (OC) screws for occipitocervical fixation via a free-hand technique.

Methods

Eight different parameters of OC morphology were studied in fifty adult skulls. Free-hand placement of OC screws was performed in five cadavers using 3.5-mm titanium polyaxial screws and a 3-mm rod construct (C0–C1–C2). Postoperative computed tomography was performed to determine the success of the screw placement and their angulation, length and effect on hypoglossal canal volume.

Results

The average length, width and height of the OC were 24.2 ± 3.6, 14.2 ± 1.9, and 10.7 ± 2 mm, respectively. The average medio-lateral, hypoglossal canal and atlanto-occipital joint angles were 38.8° medially ±5°, 7.4° rostrally ±1.9° and 23.4° caudally ±3.5°, respectively. The ten screws were successfully inserted using a free-hand technique with bicortical purchase. There was no vertebral artery injury or breach of the hypoglossal canal in any specimen. The average screw length was 22.2 ± 3.9 mm. The average medio-lateral angle was 30° medially ±6.7°. The average cranio-caudal angle was 4° caudally ±6.2°.

Conclusions

The free-hand technique of OC screw placement is a safe and viable option for occipitocervical fixation and may be a preferred alternative in selected cases. However, further studies are needed to compare its safety and reliability to other more established methods.     

Surgical treatment of chronic acromioclavicular joint dislocation using the Weaver–Dunn procedure augmented by the TightRope® system

Background

Variable outcomes resulting from the availability of multiple techniques for the treatment of chronic acromioclavicular joint (ACJ) dislocation have led to difficulty in choosing the optimal therapeutic strategy. Accordingly, the authors describe a technique for the treatment of chronic ACJ dislocation and its benefits.

Subjects and methods

The authors present a technique for surgically treating chronic ACJ dislocation using the Weaver–Dunn procedure in combination with a commercially available system (TightRope; Arthrex, Naples, FL, USA). Nine patients with chronic ACJ dislocation were surgically treated and postoperative results were evaluated.

Results

The patients were followed up for a mean of 20 months. Shoulder function was evaluated using the Constant score, with a mean score of 97 %. Compared with the uninjured side, radiography showed anatomical repositioning in the vertical plane in seven cases and slight loss of reduction in two cases. The procedure provided good functional and subjective results. All patients returned to their pre-injury activity levels.

Conclusion

The Weaver–Dunn procedure augmented by the TightRope system appeared to be an effective for treating chronic ACJ dislocation and led to excellent outcomes in terms of return to pre-injury level of function.     

Range of motion of thoracic spine in sagittal plane

Study design

Imaging study of thoracic spine.

Objective

The purpose of this study was to investigate dynamic alignment and range of motion (ROM) at all segmental levels of thoracic spine.

Summary of background data

Thoracic spine is considered to have restricted ROM because of restriction by the rib cage. However, angular movements of thoracic spine can induce thoracic compressive myelopathy in some patients. Although few previous studies have reported segmental ROM with regard to sagittal plane, these were based on cadaver specimens. No study has reported normal functional ROM of thoracic spine.

Methods

Fifty patients with cervical or lumbar spinal disease but neither thoracic spinal disease nor compression fracture were enrolled prospectively in this study (34 males, 16 females; mean age 55.4 ± 14.7 years; range 27–81 years). After preoperative myelography, multidetector-row computed tomography scanning was performed at passive maximum flexion and extension position. Total and segmental thoracic kyphotic angles were measured and ROM calculated.

Results

Total kyphotic angle (T1/L1) was 40.2° ± 11.4° and 8.5° ± 12.8° in flexion and extension, respectively (P < 0.0001). The apex of the kyphotic angle was at T6/7 in flexion. Total ROM (T1/L1) was 31.7° ± 11.3°. Segmental ROM decreased from T1/2 to T4/5 but increased gradually from T4/5 to T12/L1. Maximum ROM was at T12/L1 (4.2° ± 2.1°) and minimum at T4/5 (0.9° ± 3.0°).

Conclusions

Thoracic spine showed ROM in sagittal plane, despite being considered a stable region. These findings offer useful information in the diagnosis and selection of surgical intervention in thoracic spinal disease.     

Arthroscopically assisted stabilization of chronic AC-joint instabilities in GraftRope™ technique with an additive horizontal tendon augmentation

Purpose

A chronic symptomatic acromioclavicular joint (ACJ) instability is a possible consequence of an acute ACJ separation. Besides vertical instability a horizontal component of the instability is common in high-grade ACJ separation and clinically relevant; especially, in chronic cases. A new technique of horizontal biologic ACJ augmentation with a transacromial gracilis tendon loop as an addition to the arthroscopically assisted stabilization with the GraftRope? device is described and first clinical and sonographical results are shown.

Hypothesis

The results after arthroscopically assisted single bundle reconstruction of the coracoclavicular (CC) ligaments with an additional horizontal tendon augmentation are comparable to the results of other stabilizing techniques in chronic ACJ instabilities.

Methods

A consecutive series of 20 patients with chronic symptomatic ACJ instability was stabilized with this new technique. 16 patients were followed-up clinically and sonographically. Patient satisfaction, visual analogue scale (VAS), simple shoulder test (SST), Constant score (CS) and Taft score (TS) were assessed. Bilateral sonographic measurements were performed to evaluate recurrent instabilities. Complications and concomitant glenohumeral injuries were analyzed.

Results

Sixteen patients (n = 2 female, n = 14 male, median age 40 (21–61) years, follow-up rate 84 %) were evaluated median 13 months (range 4–27 months) after indexed operation. 11 patients had a chronic ACJ instability after Rockwood type III, and 5 patients after Rockwood type V lesion. 6 patients suffered a recurrent symptomatic instability after operative treatment. 10 patients of the group were primary stabilized with the new technique. 15 of 16 patients were satisfied with the result of the operation at the follow-up examination. The VAS was median 4.6 of 10 points (range 1.1–7.4 points). The SST reached 9 points (range 5–12 points). The adjusted CS was median 84 % (range 46–93 %) and TS median 9 points (range 5–12 points). The sonographic measurements showed a significant difference in the CC distance between the unaffected and the affected side (21.7 vs. 24.8 mm, p = 0.009). The acromioclavicular distance was median 11 mm (range 7–17 mm) after resection of the lateral clavicle. Concomitant glenohumeral injuries were arthroscopically detected in seven patients. Postoperative complications occurred in one patient (wound infection). In one case, the clavicular washer was removed due to local paresthesia after healing of the graft.

Conclusions

The arthroscopically assisted stabilization of chronic ACJ instabilities with the GraftRope? device and an additive horizontal tendon augmentation technique leads to good short-term results with a supplementary horizontal stabilization.     

Effect of a reduction of the atlanto-axial angle on the cranio-cervical and subaxial angles following atlanto-axial arthrodesis in rheumatoid arthritis

Purpose

We retrospectively investigated the radiographic findings in patients with atlanto-axial subluxation (AAS) due to rheumatoid arthritis, and clarified the effect of reduction of the atlanto-axial angle (AAA) on the cranio-cervical and subaxial angles.

Methods

Forty-one patients, consisting of 29 females and 12 males, with AAS treated by surgery were reviewed. The average patient age at surgery was 61.0 years, and the average follow-up period was 4.0 years. We investigated the AAA at the neutral position in lateral cervical radiographs before surgery and at the last follow-up. In addition, we also investigated the clivo-axial angle (CAA) and the subaxial angle (SAA) at the neutral position before and after surgery.

Results

Due to pre-operative AAA, the patients were classified into three groups as follows: (1) the kyphotic group (K group), (2) the neutral group (N group), and (3) the lordotic group (L group). The average AAA values at the neutral position in the K group before and after surgery were 6.0° and 18.1°, respectively (P < 0.001). In the N group 19.7° and 21.7°, respectively (P < 0.05), and in the L group 31.6° and 27.0°, respectively (P < 0.01). However, no significant differences in the average CAA values were found before and after surgery in all groups. Furthermore, no significant differences in the SAA values were seen before and after surgery in all groups.

Conclusions

A proper reduction of the AAA did not affect the cranial angles or induce kyphotic malalignment of the subaxial region after atlanto-axial arthrodesis. However, if we can obtain a significant and large reduction of AAA in patients showing kyphosis before surgery, then this reduction will be offset in the atlanto-occipital joint and we should therefore pay special attention to its morphology after surgery.     

A clinical morphologic study of the C2 pedicle and isthmus

Purpose

This anatomic, radiographic study investigated locational differences in the C2 pedicle and isthmus [pediculoisthmic component (PIC)] and characterized its narrowest section for clinical application in posterior C2 screw fixation.

Methods

Structures surrounding the transverse foramina of 30 dry C2s and 10 C3s were compared morphologically. Spinal CT scans of 32 Chinese adults were subjected to volume rendering and multiplanar reconstruction to identify the narrowest C2 PIC, and correlative parameters were measured and analyzed.

Results

Inferior C2 and C3 structures were morphologically similar. In superior view, the C2 superior facets lay on the transverse foramen and the upper portion between superior and inferior facets was flat (average mediolateral angle, 11.1° ± 2.4°). In inferior view, the posteroinferomedial portion of the C2 transverse foramen displayed a partially tubular structure (average mediolateral angle of projection, 42.6° ± 4.9°). Average height and width were 11.6 and 6.9 mm. The inner medullary cavity was elliptical and the middle site of endosteal diameter was 3.3 ± 1.9 mm. Medial internal cortical bone was significantly thicker than lateral bone (P < 0.01).

Conclusions

The PIC is located between superior and inferior C2 facets. The superior flat area is the isthmus and the inferomedial area connecting the inferior facet and vertebral body is the pedicle. The pedicle is partially tubular and projects posteromedially to the transverse foramen. The narrowest PIC section is the narrowest point of the C2 pedicle. Considering its thin lateral cortical bone, medial and superior pedicle screw placement and preoperative CT reconstruction are recommended.     

Symptomatic Femoroacetabular Impingement: Does the Offset Decrease Correlate With Cartilage Damage? A Pilot Study

Background

Current measures of the reduced head-neck offset such as residual deformity of slipped capital femoral epiphysis (SCFE) including the alpha angle, which measures the femoral head-neck sphericity but does not account for acetabular abnormalities, do not represent the true magnitude of the deformity and the mechanical consequences. The beta angle (angle between the femoral head-neck junction and acetabular rim) accounts for the morphology of both the acetabulum and femur and, thus, may be the more appropriate parameter for assessing SCFE deformity.

Questions/purposes

We determined (1) whether the beta angle could be reliably measured on MRI; and (2) whether the beta angle correlates with the cartilage status.

Methods

We recruited 10 adult patients (mean age, 28 years) with symptomatic cam femoroacetabular impingement and 15 asymptomatic volunteers (mean age, 24 years) to have three-dimensional MRI including delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) for cartilage status assessment. Corresponding alpha angles, beta angles, and acetabular dGEMRIC indices were obtained in seven radial reformats to assess the hip in seven regions (anterior to superior and posterior).

Results

We noted high reproducibility for both alpha and beta angle measurements. The dGEMRIC indices correlated with beta angles in the superoinferior and superior regions but not the alpha angles.

Conclusions

Beta angle measurement in radial MR images is reproducible and appears to correspond to cartilage damage in the superior regions of the hip. The beta angle may be a useful parameter to assess hip deformity in the followup of SCFE although further confirmation is warranted.     

Development and validation of a quantitative method to assess pedicle screw loosening in posterior spine instrumentation on plain radiographs

Purpose

Currently, the diagnosis of pedicle screw (PS) loosening is based on a subjectively assessed halo sign, that is, a radiolucent line around the implant wider than 1 mm in plain radiographs. We aimed at development and validation of a quantitative method to diagnose PS loosening on radiographs.

Methods

Between 11/2004 and 1/2010 36 consecutive patients treated with thoraco-lumbar spine fusion with PS instrumentation without PS loosening were compared with 37 other patients who developed a clinically manifesting PS loosening. Three different angles were measured and compared regarding their capability to discriminate the loosened PS over the postoperative course. The inter-observer invariance was tested and a receiver operating characteristics curve analysis was performed.

Results

The angle measured between the PS axis and the cranial endplate was significantly different between the early and all later postoperative images. The Spearman correlation coefficient for the measurements of two observers at each postoperative time point ranged between 0.89 at 2 weeks to 0.94 at 2 months and 1 year postoperative. The angle change of 1.9° between immediate postoperative and 6-month postoperative was 75 % sensitive and 89 % specific for the identification of loosened screws (AUC = 0.82).

Discussion

The angle between the PS axis and the cranial endplate showed good ability to change in PS loosening. A change of this angle of at least 2° had a relatively high sensitivity and specificity to diagnose screw loosening.     

Skip pedicle screw fixation combined with Ponte osteotomy for adolescent idiopathic scoliosis

Purpose

This study aimed to determine whether Ponte osteotomy combined with skip pedicle screw fixation (SPSF) can improve the correction rate and restore thoracic kyphosis for patients with adolescent idiopathic scoliosis.

Methods

Surgical time, blood loss, preoperative Cobb angle of the main thoracic curve, flexibility, Cobb angle at 1 year after surgery, thoracic curve correction rate, and Cincinnati correction index (CCI) were determined for both the Ponte (n = 17) and non-Ponte (control; n = 21) groups. Furthermore, kyphotic angles at T5–T12 before and 1 year after the surgery were measured.

Results

The following measurements were obtained for the Ponte and control groups, respectively: surgical time, 236 ± 13 and 187 ± 9 min; blood loss, 1,141 ± 150 and 745 ± 120 g; preoperative Cobb angle of the main thoracic curve, 52.5° ± 10.4° and 51.5° ± 9.2°; flexibility, 31.7 ± 13.2 and 45.1 ± 12.3 % (p = 0.003); thoracic curve correction rate, 62.0 ± 2.5 and 63.6 ± 2.5 %; CCI, 2.2 ± 0.2 and 1.5 ± 0.1 (p = 0.003); preoperative kyphotic angle at T5–T12, 11.3° ± 11.2° and 13.0° ± 9.0°; and kyphotic angle at T5–T12 at 1 year after the surgery, 21.8° ± 1.7° and 24.2° ± 1.9°.

Conclusion

Ponte osteotomy was combined with SPSF in case of rigid curve. CCI was significantly greater in the Ponte group. Postoperative thoracic kyphotic angles were identical in both groups.     

Cardinal and deep uterosacral ligament lines of action: MRI based 3D technique development and preliminary findings in normal women

Introduction and hypothesis

The cardinal ligament (CL) and deep uterosacral ligament (US) play a critical role in utero-vaginal support. This study aims to quantify their geometrical relationships in living women using a MRI-based 3D technique.

Methods

The angles between ligaments, the ligaments length and curvature were assessed on 3D models constructed from twenty MRIs of volunteers with normal support. How angle variation theoretically affects ligament tension was investigated using a simplified biomechanical model.

Results

The CLs are 18.1 °?±?6.8 °(SD) from the cephalic-caudal body axis , and the USs are dorsally directed and 92.5 °?±?13.5 from the body axis. The CLs are longer and more curved than US. The theoretical calculated tension on CL is 52 % larger than that on US.

Conclusions

The CL is relatively parallel to the body axis while the US is dorsally directed. The tensions on these ligaments are affected by their orientations.     

Hat die Nachtorthese in der Skoliosetherapie noch eine Berechtigung?

Background

The aim of our investigation was to evaluate the effectiveness of isolated night-time treatment in idiopathic scoliosis.

Methods

Twenty-two children (average age 11.9 years; range 5–12 years) underwent treatment with the“Dresdner night-time brace.” We indicated brace treatment in all children with a Cobb angle of 20–25° and also in those with an angle of 15–19° in cases of progression. Over a follow-up period of 25 months, clinical and radiological observations were made.

Results

A primary correction of 82.2% was obtained. The mean Cobb angle in an upright position without orthosis before treatment was 20.2°. At the end of treatment, this angle reached 15.8°. Operations were able to be avoided completely. In only three cases with radiographic progression (development of angles >25°), part-time bracing had to be stopped and changed to full-time bracing. We observed an overall success rate of 86.4% (patients with improved Cobb angles or halted progression).

Conclusion

We were able to show a positive effect of part-time bracing in selected patients with mild scoliosis and a higher risk of progression. The negative medical and psychosocial consequences of 23-h brace treatment can therefore be avoided in certain patients.     

Die belastungsstabile Lapidus-Arthrodese bei Hallux-valgus-Deformität mittels IVP-Plattenfixateur (V-TEK®-System)

Objective

Correction of hallux valgus deformities without loss of toe length. Achievement of full weight-bearing.

Indications

Hallux valgus with intermetatarsal angle of more than 20°. Hypermobility of the first metatarsal bone combined with instability. Recurrence of hallux valgus deformity. Hallux limitus combined with metatarsus primus elevatus. Painful arthrosis of the metatarsal-cuneiform-medial joint (TMT 1).

Contraindications

Arterial occlusive disease. Infection of the foot. Nicotine abuse. Strict verification of indication in patients with diabetes mellitus.

Surgical technique

Lateral release of the proximal phalanx joint of the hallux with tenotomy of the adductor hallucis tendon. Resection of the medial pseudoexostosis. Cartilage removal at the joint basis of the metatarsus 1 and the joint basis of the medial cuneiform bone to prepare for the corrective arthrodesis. Proximal osteotomy of the metatarsus 1. Lateralization and, if required, derotation of the distal metatarsus 1 segments using a special L-type chisel to prepare the intramedullary bed for the plate, going right into the medial cuneiform. Insertion of the IVP plate and fixation using stable screws in the correct angle. Medial capsuloraphy.

Postoperative management

Early functional rehabilitation with increasing weight-bearing using a special shoe for 6–8 weeks. Full weight-bearing usually after 2 weeks. Physical therapy, lymphatic drainage, cryotherapy. Leg elevation.

Results

In all, 21 consecutive patients, 19 women, 2 men, between 41 and 75 years of age (mean age 62.3 years) were included. Mean follow-up was 21 months (12–27 months). Preoperative hallux valgus angle (48°; range 40–63°) improved to 15° (range 6–28°). The intermetatarsal angle averaged 18° (range 12–27°) preoperatively and 8° (range 7–10°) postoperatively. The Kitaoka score improved from 47 points (37–49 points) preoperatively to 81 points (77–86 points) postoperatively. Complications included loosening of screws in 4 cases. All were treated by partial hardware removal under local anesthesia without further sequelae. In 5 cases, prolonged wound secretion (up to 5 weeks) healed without infection.