Application of transforaminal lumbar interbody fusion in old thoracolumbar fracture and dislocation

Abstract

Background

The main indications for surgery for old thoracolumbar fractures are pain, progressive deformity, neurological damage, or increasing neurological deficit. These fractures have been one of the greatest therapeutic challenges in spinal surgery. Anterior, posterior, or combined anterior and posterior procedures have been successful to some extent. As far as we know, there is no report in the literature of transforaminal lumbar interbody fusion (TLIF) for old thoracolumbar fracture and dislocation.

Methods

Case report.

Results

A 26-year-old man with old fracture and dislocation of T12/L1 was treated with TLIF. At 12 months' follow-up, multi-slice computed tomography (CT) scans showed that solid fusion had been achieved between T12 and L1. Back pain had resolved completely at 2-year follow-up.

Conclusions

We performed TLIF for in a man with old fracture and dislocation of T12/L1, with good clinical outcome. TLIF might be an option in the treatment of old thoracolumbar fracture.     

More than 5-Year Follow-up Results of Two-Level and Three-Level Posterior Fixations of Thoracolumbar Burst Fractures with Load-Sharing Scores of Seven and Eight Points

Background

The development of pedicle screw-based posterior spinal instrumentation is recognized as one of the major surgical treatment methods for thoracolumbar burst fractures. However, the appropriate level in posterior segment instrumentation is still a point of debate. To assesses the long-term results of two-level and three-level posterior fixations of thoracolumbar burst fractures that have load-sharing scores of 7 and 8 points.

Methods

From January 1998 to May 2009, we retrospectively analyzed clinical and radiologic outcomes of 45 patients with thoracolumbar burst fractures of 7 and 8 points in load-sharing classification who were operated on using two-level posterior fixation (one segment above and one segment below: 28 patients, group I) or three-level posterior fixation (two segments above and one segment below: 17 patients, group II). Clinical results included the grade of the fracture using the Frankel classification, and the visual analog score was used to evaluate pain before surgery, immediately after surgery, and during follow-up period. We also evaluated pain and work status at the final follow-up using the Denis pain scale.

Results

In all cases, non-union or loosening of implants was not observed. There were two screw breakages in two-level posterior fixation group, but bony union was obtained at the final follow-up. There were no significant differences in loss of anterior vertebral body height, correction loss, or change in adjacent discs. Also, in clinical evaluation, there was no significant difference in the neurological deficit of any patient during the follow-up period.

Conclusions

In our study, two-level posterior fixation could be used successfully in selected cases of thoracolumbar burst fractures of 7 and 8 points in the load-sharing classification.     

An unusual stress fracture: Bilateral posterior longitudinal stress fracture of tibia

INTRODUCTION

Stress fractures (SF) occur when healthy bone is subjected to cyclic loading, which the normal carrying range capacity is exceeded. Usually, stress fractures occur at the metatarsal bones, calcaneus, proximal or distal tibia and tends to be unilateral.

PRESENTATION OF CASE

This article presents a 58-year-old male patient with bilateral posterior longitudinal tibial stress fractures. A 58 years old male suffering for persistent left calf pain and decreased walking distance for last one month and after imaging studies posterior longitudinal tibial stress fracture was detected on his left tibia. After six months the patient was admitted to our clinic with the same type of complaints in his right leg. All imaging modalities and blood counts were performed and as a result longitudinal posterior tibial stress fractures were detected on his right tibia.

DISCUSSION

Treatment of tibial stress fracture includes rest and modified activity, followed by a graded return to activity commensurate with bony healing. We have applied the same treatment protocol and our results were acceptable but our follow up time short for this reason our study is restricted for separate stress fractures of the posterior tibia.

CONCLUSION

Although the main localization of tibial stress fractures were unilateral, anterior and transverse pattern, rarely, like in our case, the unusual bilateral posterior localization and longitudinal pattern can be seen.     

Body composition modifications in people with chronic spinal cord injury after supervised physical activity

Context

The Thoracolumbar Injury Classification System (TLICS) has been recently described to help surgeons in the decision-making process of thoracolumbar spinal trauma.

Objective

To analyze the potential relationships between the TLICS scores with the Arbeitsgemeinschaft für Osteosynthesefragen (AO) Spine System and patient''s neurological status.

Methods

Literature analysis of the potential scored injuries in the TLICS system, based on its individual scores, its total score, and its suggested proposed treatment, correlating these with the AO system and neurological status.

Results

Findings are presented according to the TLICS score. Patients with a TLICS 1–3 points, receiving conservative treatment, are AO type A injuries, generally neurologically intact. TLICS 4 group also included AO type A fractures, neurologically ranging from intact to complete spinal cord injury. TLICS 5–10 points includes AO type B and C injuries, regarding their neurological status, and burst fractures (AO type A) with concomitant neurological injury and most of the patients with incomplete deficits and cauda equina syndrome.

Conclusions

As a general overview, according to the TLICS, patients without neurological deficit and with AO type A injuries are conservatively treated. AO type B and C injuries are managed surgically, with regard to neurological status. Patients with cauda equina or incomplete injuries also received a higher severity score. Controversies still exist regarding the management of unstable burst fractures without neurological status. The role of the posterior ligamentous complex status and the magnetic resonance imaging in the decision-making process require more clinical evidence.     

Posterior acetabular arc angle of unstable posterior hip fracture–dislocation

Purpose

Posterior hip fracture–dislocation needs stability evaluation. A previous study in the normal acetabulum has shown that the coronal posterior acetabular arc angle (PAAA) could be used to assess an unstable posterior hip fracture. Our study was designed to assess PAAA of unstable posterior hip fracture–dislocation and whether posterior acetabular wall fracture involves the superior acetabular dome.

Methods

Using coronal computed tomography (CT) of the acetabulum and 3D reconstruction of the lateral pelvis, we measured coronal, vertical PAAA and posterior acetabular wall depth of 21 unstable posterior hip fracture–dislocations and of 50 % normal contralateral acetabula. Posterior acetabular wall fracture was assessed to determine whether the fracture involved the superior acetabular dome and then defined as a high or low wall fracture using vertical PAAA in reference to the centroacetabulo–greater sciatic notch line.

Results

The coronal PAAA of unstable posterior hip fracture–dislocations and of 50 % of the posterior acetabular wall of normal the contralateral acetabulum were 54.48° (9.09°) and 57.43° (5.88°) and corresponded to 15.06 (4.39) and 15.61 (2.01) mm of the posterior acetabular wall without significant difference (p > 0.05). The vertical PAAA of unstable posterior hip fracture–dislocation was 101.67° (20.44°). There were 16 high posterior acetabular wall fractures with 35.00 (16.18) vertical PAAA involving the acetabular dome and 5 low wall fractures. High posterior wall fractures resulted in four avascular necroses of the femoral head, three sciatic nerve injuries and one osteoarthritic hip.

Conclusion

Coronal and vertical PAAA of unstable posterior hip fracture–dislocations were 54.48° and 101.67°. Vertical PAAA assesses high or low posterior acetabular wall fracture by referring to the centroacetabulo–greater sciatic notch line. High posterior wall fracture seems to be the most frequent and is involved with many complications.     

Monosegmental fixation for the treatment of fractures of the thoracolumbar spine

Background:

A short vertebral arthrodesis has been one of the objectives of the surgical treatment of fractures of the thoracolumbar spine. We present here clinical, functional and radiographic outcome obtained after monosegmental fixation (single posterior or combined anterior and posterior) of specific types of unstable thoracolumbar fractures.

Materials and Methods:

Twenty four patients with fractures of the thoracolumbar spine submitted to monosegmental surgical treatment (Group I - 18 single posterior monosegmental fixations and Group II - 6 combined anterior and posterior fixations) were retrospectively evaluated according to clinical, radiographic and functional parameters. The indication for surgery was instability or neurological deficit. All the procedures were indicated and performed by the senior surgeon (Helton LA Defino).

Results:

The patients from group I were followed-up from 2 to 12 years (mean: 6.65±2.96). The clinical, functional and radiographic results show that a single posterior monosegmental fixation is adequate and a satisfactory procedure to be used in specific types of thoracolumbar spine fractures, The patients from group II were followed-up from 9 to 15 years (mean: 13 ± 2,09 years). On group II the results of clinical evaluation showed moderate indices of residual pain and of satisfaction with the final result. The values obtained by functional evaluation showed that 66.6% of the patients were unable to return to their previous job and presented a moderate disability index (Oswestry = 16.6) and a significant reduction of quality of life based on the SF-36 questionnaire. Radiographic evaluation showed increased kyphosis of the fixed vertebral segment during the late postoperative period, accompanied by a reduction of the height of the intervertebral disk.

Conclusion:

It is possible to stabilize the fractures which have an anterior good load-bearing capacity by a standalone posterior monosegmental fixation. However this procedure, even with an anterior support is not suitable for fracture involving the vertebral body.     

Pediatric open elbow dislocation without fracture: A case report

INTRODUCTION

Elbow dislocations in children are rare injuries. These injuries are often in the form of complex injuries that is accompanied by the median nerve damage and medial epicondyle fracture in the pediatric age group. Open elbow dislocation without fracture in the pediatric age group has been reported very rarely in the literature.

PRESENTATION OF CASE

The purpose of this study is to present an 8-year-old patient who has open elbow dislocation without fracture accompanying with brachial artery injury. In the clinical examination of the patient, there was an open wound in the transverse antecubital region. After repair of brachial artery injury, open reduction was performed under general anesthesia. In the postoperative clinical examination at 6 months, left elbow flexion was 140°, extension was full and there were no deficit in the supination and pronation of the forearm.

DISCUSSION

Elbow dislocation without fracture in pediatric patients is a very rare injury. Usually the trauma mechanism of elbow dislocation is falling on outstretched hand with elbow in approximately 30° of flexion. However our patient had fallen on outstretched hand with elbow in full extension. Although this type of trauma mechanism is typical for supracondylar humerus fractures in pediatric age group, in our patient an open posterior elbow dislocation without fracture had occurred.

CONCLUSION

Pediatric elbow dislocations are rare injuries and the management of these injuries can be technically demanding due to concurrent neurovascular injuries. An open dislocation without fracture is very rare and it should be treated with immediate intervention, an effective teamwork and good rehabilitation.     

Treatment of acute thoracolumbar burst fractures with kyphoplasty and short pedicle screw fixation: Transpedicular intracorporeal grafting with calcium phosphate: A prospective study

Background:

In the surgical treatment of thoracolumbar fractures, the major problem after posterior correction and transpedicular instrumentation is failure to support the anterior spinal column, leading to loss of correction and instrumentation failure with associated complaints. We conducted this prospective study to evaluate the outcome of the treatment of acute thoracolumbar burst fractures by transpedicular balloon kyphoplasty, grafting with calcium phosphate cement and short pedicle screw fixation plus fusion.

Materials and Methods:

Twenty-three consecutive patients of thoracolumbar (T₉ to L₄) burst fracture with or without neurologic deficit with an average age of 43 years, were included in this prospective study. Twenty-one from the 23 patients had single burst fracture while the remaining two patients had a burst fracture and additionally an adjacent A1-type fracture. On admission six (26%) out of 23 patients had neurological deficit (five incomplete, one complete). Bilateral transpedicular balloon kyphoplasty with liquid calcium phosphate to reduce segmental kyphosis and restore vertebral body height and short (three vertebrae) pedicle screw instrumentation with posterolateral fusion was performed. Gardner kyphosis angle, anterior and posterior vertebral body height ratio and spinal canal encroachment were calculated pre- to postoperatively.

Results:

All 23 patients were operated within two days after admission and were followed for at least 12 months after index surgery. Operating time and blood loss averaged 45 min and 60 cc respectively. The five patients with incomplete neurological lesions improved by at least one ASIA grade, while no neurological deterioration was observed in any case. The VAS and SF-36 (Role physical and Bodily pain domains) were significantly improved postoperatively. Overall sagittal alignment was improved from an average preoperative 16° to one degree kyphosis at final followup observation. The anterior vertebral body height ratio improved from 0.6 preoperatively to 0.9 (P<0.001) postoperatively, while posterior vertebral body height improved from 0.95 to 1 (P<0.01). Spinal canal encroachment was reduced from an average 32% preoperatively to 20% postoperatively. Cement leakage was observed in four cases (three anterior to vertebral body and one into the disc without sequalae). In the last CT evaluation, there was a continuity between calcium phosphate and cancellous vertebral body bone. Posterolateral radiological fusion was achieved within six months after index operation. There was no instrumentation failure or measurable loss of sagittal curve and vertebral height correction in any group of patients.

Conclusions:

Balloon kyphoplasty with calcium phosphate cement secured with posterior short fixation in the thoracolumbar spine provided excellent immediate reduction of posttraumatic segmental kyphosis and significant spinal canal clearance and restored vertebral body height in the fracture level.     

Irreducible dorsal distal radius fracture-dislocation with accompanying dorsal displacement of flexor tendons and median nerve: A rare type of injury

INTRODUCTION

High energy distal radius fractures may cause significant soft tissue injuries. Dorsal displacement of median nerve and flexor tendons to dorsal compartment between distal radioulnar joint was an unreported type of soft tissue injury.

PRESENTATION OF CASE

35-Year male admitted following fall from height diagnosed as closed distal radius fracture with dorsal displacement. The patient had no flexion and extension of all fingers with loss of sensation. Radial artery pulse was not palpable. Radiography and CT imaging revealed distal radius fracture with dorsal displacement with dorsal carpal dislocation. After failure of closed reduction, operative treatment was performed. At surgery, flexor tendons and median nerve was found to be placed at dorsal compartment. Reduction of the soft tissues was facilitated by distraction of distal radioulnar joint.

DISCUSSION

Dorsal displacement of volar structures as the result of fracture dislocation was found to be an unreported type of injury. Difficulty during reduction of dorsally displaced structures is an important feature of the case.

CONCLUSION

For severely displaced and deformed distal radial fractures and fracture dislocations, threshold for operative treatment should be kept low.     

Percutaneous kyphoplasty combined with the posterior screw-rod system in treatment of osteoporotic thoracolumbar fractures

Background:

The osteoporotic vertebral compression fractures (OVCF) have attracted more and more attention due to increase in life span globally and aging population. Percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) have been popularized rapidly by virtue of their unique advantage in minimal invasiveness. We analysed our results in osteoporotic thoracolumbar fractures using percutaneous kyphoplasty and posterior screw rod system. To investigate the possibility of treatment of rupture of the posterior vertebral osteoporotic fractures by means of kyphoplasty combined with the posterior screw-rod system.

Materials and Methods:

Twenty six patients (65 years of age or older) with the single spine fractures included in study. The preoperative bone mineral density was measured by dual-energy X-ray. The PKP was done in all the cases. Decompression was done if neurological symptoms were present.

Results:

The results demonstrated osteoporosis with BMD T value ≤ −2.5; injured posterior vertebral body (3 cases) had shown the whole damage accompanied by neurological symptoms through X-ray or CT. After 2 days, the remaining patients of back pain symptoms were relieved or disappeared except for three cases of patients with decompression incision. VAS score and Cobb angle changed from preoperative 8.23 ± 0.17 and 28.7 ± 0.33° respectively to postoperative 3.77 ± 0.44 and 3.8 ± 0.2° respectively.

Conclusion:

Treatment of rupture of the posterior vertebral osteoporotic thoracolumbar fractures by means of kyphoplasty combined with posterior screw-rod system is a safe, effective procedure.     

Temporary occipito-cervical stabilization of a unilateral occipital condyle fracture

IntroductionInjuries of the occipital condyles are rare. While the majority of occipital condyle fractures can be treated conservatively, surgery is recommended in craniocervical misalignment and instability. Open reduction and temporary occipito-cervical stabilization might be an alternative to fusion or halo treatment.

Materials and methods

This Grand Round case presentation describes temporary C0–C3 stabilization in a 29-year-old man who was involved in a car accident. Radiological examination revealed a rotational burst fracture (type AO C3.1) of C7, and a slight displaced right occipital condyle fracture (Anderson/Montesano type III) with rotational misalignment of the C0–C2 complex.

Results

The C7 fracture was stabilized and fused from anterior and posterior. The occipital condyle fracture was reduced and temporarily stabilized from C0–C3 from posterior. Bony healing occurred after 6 months and consequently the internal fixator was removed to preserve upper cervical mobility.     

Posterior approach lumbar and thoracolumbar hemivertebra resection in congenital scoliosis in children under 10 years of age: results with 3 years mean follow up

Introduction

The authors present 15 cases of congenital scoliosis with lumbar or thoracolumbar hemivertebra in children under 10 years of age (mean age at the time of surgery was 5.5 years). Patients were treated by posterior hemivertebra resection and pedicle screws two levels stabilization or three or more levels stabilization in the case of deformity above or under hemivertebra or for severe curve deformities.

Materials and methods

All operated patients had worsening curves; mean follow up was 40 months. The mean scoliosis curve value was 44° Cobb, and reduced to a mean 11° Cobb after surgery. The mean segmental kyphosis value was 19.7° Cobb, and reduced to a mean −1.8° Cobb after surgery. We did not consider total dorsal kyphosis value as all hemivertebras treated were at lumbar or thoracic lumbar level. No major complications emerged (infections, instrumentation mobilization or failure, neurological or vascular impairment) and only one pedicle fracture occurred.

Results

Our findings show that the hemivertebra resection with posterior approach instrumentation is an effective procedure, which has led to significant advances in congenital deformity control, which include excellent frontal and sagittal correction, excellent stability, short segment arthrodesis, low neurological impairment risk, and no necessity for further anterior surgery.

Conclusion

Surgery should be considered as soon as possible in order to avoid severe deformity and the use of long segment arthrodesis. The youngest patient we treated, with a completed dossier at the end the follow up was 24 months old at the time of surgery; the youngest patient treated by this procedure was 18 months old at the time of surgery.     

Traumatic hyoid bone fracture �C a case report and review of the literature

Objective:

To present a case of traumatic hyoid bone fracture and a review of the literature

Rationale:

Traumatic hyoid bone fractures are rare, however with the increasing popularity of martial arts the incidence of traumatic hyoid bone fracture may increase in prevalence.

Clinical Features:

A thirteen year old taekwondo athlete collapsed after receiving a kick to the anterior neck. Following first aid emergency care the athlete reported pain with speaking and swallowing and was suffering from dyspnea. Ecchymosis and tenderness were noted over the hyoid bone.

Intervention and Outcome:

Lateral radiographs revealed fracture of the hyoid. Patient was sent home with analgesics and instructed to rest. The athlete was cleared for sport at 4 weeks post injury.

Conclusion:

Ensuring airway integrity and screening for signs of laryngeal laceration are essential in the management of suspected hyoid bone fractures. Observation for 48–72 hours is highly recommended.     

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.     

The effect of minimally displaced posterior malleolar fractures on decision making in minimally displaced lateral malleolus fractures

Purpose

Despite the high incidence of cases of minimally displaced lateral or posterior malleolus ankle fractures, treatment guidelines are still an issue of controversy. The purpose of this study was to delineate treatment preferences among orthopaedic surgeons in these fractures with and without concomitant posterior malleolus fractures. We hypothesized that concomitant minimally displaced fractures of the posterior malleolus can shift treatment preference towards operative intervention.

Methods

A questionnaire-based study was conducted among orthopaedic surgeons attending the 2012 European Federation of National Associations of Orthopaedics and Traumatology Conference (EFORT) in Berlin, Germany. Treatment preferences were reported for minimally displaced lateral malleolus fractures seen on radiographs and were then compared with treatment preferences when computed tomography (CT) was added revealing a concomitant minimally displaced posterolateral fracture of the posterior malleolus.

Results

The cohort comprised 177 surgeons from all six continents. When radiographs showing a minimally displaced lateral malleolus fracture were presented, nonoperative management was indicated by 35 % (62) of participants, whereas 65 % (115) preferred operative intervention. After CT views were added showing an accompanying minimally displaced posterolateral posterior malleolus fracture, 79 % (140) suggested operative intervention and only 21 % (37) advocated nonoperative management (p = 0.03).

Conclusions

Most surgeons prefer open reduction with internal fixation for minimally displaced lateral malleolar fractures. The presence of concomitant posterior malleolus fractures in these cases shifts treatment preference further towards open reduction with internal fixation. Because the posterior malleolus fragment might not be well delineated on standard ankle radiographs, a high index of suspicion is warranted, and the use of CT should be considered in these cases.     

Motion in the unstable thoracolumbar spine when spine boarding a prone patient

Introduction

Previous research has found that the log roll (LR) technique produces significant motion in the spinal column while transferring a supine patient onto a spine board. The purpose of this project was to determine whether log rolling a patient with an unstable spine from prone to supine with a pulling motion provides better thoracolumbar immobilization compared to log rolling with a push technique.

Methods

A global instability was surgically created at the L1 level in five cadavers. Two spine-boarding protocols were tested (LR Push and LR Pull). Both techniques entailed performing a 180° LR rotation of the prone patient from the ground to the supine position on the spine board. An electromagnetic tracking device registered motion between the T12 and L2 vertebral segments. Six motion parameters were tracked. Repeated-measures statistical analysis was performed to evaluate angular and translational motion.

Results

Less motion was produced during the LR Push compared to the LR Pull for all six motion parameters. The difference was statistically significant for three of the six parameters (flexion–extension, axial translation, and anterior–posterior (A–P) translation).

Conclusions

Both the LR Push and LR Pull generated significant motion in the thoracolumbar spine during the prone to supine LR. The LR Push technique produced statistically less motion than the LR Pull, and should be considered when a prone patient with a suspected thoracolumbar injury needs to be transferred to a long spine board. More research is needed to identify techniques to further reduce the motion in the unstable spine during prone to supine LR.     

Bilateral intertrochanteric and femoral diaphyseal fractures with unilateral proximal tibial fracture: A case report and review of the literature

INTRODUCTION

Bilateral intertrochanteric femur fractures are relatively rare injuries. This study aims to present a case of a patient with simultaneous bilateral intertrochanteric femur fractures and femoral diaphyseal fractures and proximal tibial fracture with his twelve years follow-up.

PRESENTATION OF CASE

A 44-year-old man presented to emergency department after a motor vehicle accident. Bilateral intertrochanteric femur fractures (OTA classification – 31A.1.2) and bilateral femoral diaphyseal fractures (OTA classification – 32A.2) and nondisplaced right proximal tibial fracture (OTA classification – 41B.1) were determined in radiographs. Following closed reduction, fractures were fixed with intramedullary nails bilaterally. Proximal tibial fracture was fixed with cannulated screws following open reduction. At twelfth year follow-up he was able to do his daily activities with minimal limitation.

DISCUSSION

High energy traumas, stress fractures, systemic disorders (osteomalacia, chronic renal failure), steroid treatments, seizures and electric injuries are possible causes for bilateral hip factures. However bilateral femoral diaphyseal fractures are mostly due to high energy traumas. Long-term biphosphonate use may also cause bilateral fractures. Single-stage surgery should be performed in order to avoid secondary damages of surgical interventions. All fractures of our patient were fixed in a single session. This prevented further deterioration of patient''s status and made rehabilitation easy.

CONCLUSION

Careful evaluation of all systems should be performed in multi-trauma patients to find out concomitant injuries. Single staged surgical treatment may decrease morbidities.