MINIMALLY INVASIVE OSTEOSYNTHESIS OF PELVIC RING INJURIES WITH POLYTRAUMA

MINIMALLY INVASIVE OSTEOSYNTHESIS OF PELVIC RING INJURIES WITH POLYTRAUMA

Bondarenko A.V., Kruglykhin I.V., Plotnikov I.A., Talashkevich M.N.

  Altay State Medical University, Regional Clinical Hospital of Emergency Medical Care, Barnaul, Russia  

Improvement in techniques of intensive care promoted the increase in survival of patients with severe pelvic injury, resulting in appearance of some new problems relating to development of complications, increasing amount of unsatisfactory outcomes and disability [1-3]. Patients with pelvic injury often demonstrate pelvic ring deformations, disproportions in length of extremities, development of contractures, degenerative lesions of joints and articulations, disordered pelvic organs functioning, neurological and vascular disorders [4-7].
For preservation of supporting and movement, pelvic ring injuries require for precise reposition – accurate anatomic alignment of injured structures, fixation stability, which allows achieving early function consisting in early activation of the patient which is especially necessary in treatment of polytrauma (PT) [8-10].
The use of conservative techniques for these purposes is unacceptable. Opened surgical interventions, which are traditionally used for pelvic ring reconstruction, are quite complex and high-level, are associated with significant surgical aggression and high intrasurgical blood loss, and their realization in PT is often impossible owing to severe condition of patients [11-13]. All of these dictate the need for wide practical implementation of minimally invasive osteosynthesis (MIO) methods, which do not worsen patients’ condition and allow carrying out reposition and stable fixation of the pelvic ring at early stages of treatment.
At the present time in our and foreign countries, internal transcutaneous osteosynthesis of the posterior semi-ring with use of cannulated screws is used. As compared the traditional techniques, the indicated method is characterized by low traumatic potential and sufficient strength of fixation, which allows mobilizing the patient and realizing the load from body weight and walking within the first days after surgery [14-18].
Moreover, some unsolved issues of the use of transcutaneous osteosynthesis for the posterior complex exist:
1. Which pelvic injuries require for its realization?
2. Is there a necessity for reposition and stabilization of the anterior complex? If yes, then what is the sequence?
3. Is it possible to use cannulated screws for stabilization of sacral fractures?
Study objective – to find out the features of the use of ileosacral transcutaneous cannulated screws in the reconstruction of pelvic ring injuries in patients with PT. 

MATERIALS AND METHODS

For the last 10 years, MIO for the posterior complex with cannulated screws was used for pelvic ring reconstruction for 297 patients with PT. Among them, 196 patients did not receive fixation of the anterior complex, 101 patients received its additional fixation. For this purpose, 43 patients received external fixators (EF), 58 – plates and screws.
There were 162 men (54.5 %) and 135 women (45.5 %), the age of 10-79 (mean age – 34). There were 156 (52.5 %) working patients, 83 (27.9 %) non-working patients of working age, 58 (19.6 %) students and retired persons.
The causes of injuries were road traffic accidents – 202 (68.1 %), falling from height – 82 (27.6 %), pelvic compression from heavy objects – 13 (4.3 %).
The associated injury was identified in 213 (71.7 %) patients, multiple fractures – in 81 (27.2 %), combined injury – in 3 (1.1 %). PT with ISS [19] of 17-25 points was identified in 146 (49.2 %), 26-40 – in 89 (29.9 %), more than 41 – in 62 (20.9 %) patients. Traumatic brain injuries of various severity were diagnosed in 154 (51.9 %), injuries to internal organs – 133 (44.8 %), locomotor system injuries in other regions – in 160 (53.8 %), burns – in 3 (1.1 %).
AO classification was used for estimation of pelvic ring injuries [20]. Osteosynthesis for the posterior complex in stable pelvic ring injuries (type A) was not conducted. Partially stable injuries (type B) with horizontal and rotational instability after injuries from anterioposterior and external compression were noted in 196 (65.9 %) patients, unstable (type C) with vertical instability as result of injuries from shift or combined impacts – in 101 (34.1 %). 172 (57.9 %) patients had unilateral injuries to the posterior complex, 125 (42.1 %) patients – bilateral ones. Totally, 297 patients had 422 injuries to structures of the posterior pelvic semi-ring. Fractures of bones (the sacrum and the iliac bone) were diagnosed in 198 cases, lacerations of ligamentous apparatus in the sacroiliac joints (SIJ) – in 224.
At admission, at the stage of critical care, 71 patients received the temporary fixation with external fixing devices – pelvic pliers and EF. The indication for urgent stabilization was opened and mechanically and hemodynamically unstable injuries to the pelvic ring.
The pelvic reconstruction with cannulated screws was carried out in compliance with patients’ condition stabilization. Within the first three days post injury, osteosynthesis of the posterior complex was conducted for 34 patients, from 3 days to 3 weeks – for 229, more than 3 weeks – for 34. The terms of carrying out of operations varied from 1 to 78 days. The median (Me) – 10 days, interquartile range – 6-15 days. Pelvic reconstruction was conducted with the metal constructs from Synthes (Switzerland) and Osteomed (Russia).
Totally, osteosynthesis of the posterior complex with cannulated screws for closed injuries was used for 266 patients, for opened injuries – for 31, for unilateral ones – for 172, for bilateral ones – for 125.
As the main technique without anterior pelvic semi-ring stabilization, the posterior complex osteosynthesis with screws was carried out for 196 patients. Among them, opened fractures were 15 (7.7 %) and were presented by bladder laceration in 12 cases and by urethra laceration in 3. 161 patients had injuries of type B, 35 patients – type C, 124 – unilateral injuries, 72 – bilateral ones. Injuries to the anterior semi-ring were in 3 patients with pubic symphysis lacerations, in 193 – with fractures of pubic bones. SIJ rupture as the main injury to the posterior pelvic complex was in 75 patients, iliac and sacral fractures – in 121.

Figure 1. X-ray images of the patient B., age of 31, a pelvic ring injury 61-B1: a) before reconstruction; b) after fixation of the posterior complex with the screw (7.3 mm canal)

  


As a rule, isolated osteosynthesis with cannulated screws for the posterior complex was used for patients without displacement of fragments or with slight displacement. In case of displacements exceeding 2.5 cm in length and 1 cm in width, reposition and additional fixation of the anterior semi-ring was required in all cases. The question of subsequence of the stages of surgical intervention arose. Which pelvic semi-ring is to be restored firstly: anterior or posterior? Reposition and stable fixation of fragments of the anterior complex promoted restoration of correct relationships between the posterior pelvic structures in horizontal or rotational instability that significantly simplified the realization of transcutaneous fixation of the posterior complex. In case of injuries from dislocation or in mixed mechanism of with vertical or posterior displacement, the posterior semi-ring was restored first of all, and then – the anterior one, because some problems in reposition of the anterior complex appeared in other case.As addition to the posterior complex osteosynthesis, 43 patients received the anterior complex osteosynthesis with EF (Fig. 2). Among them, opened injuries were in 10 (23.3 %) and were presented by urinary bladder lacerations in 7 patients, urethra lacerations – in 2, opened fracture of iliac wing – in 1. 18 patients had type B injuries, 25 – type C, 22 – unilateral, 21 – bilateral. 10 patients had pubic symphysis ruptures, 33 – fractures of pubic bone branches. Among 10 patients with pubic symphysis laceration, 2 patients had the posterior pelvic complex injuries of type B, 8 – type C. SIJ as the main injury to the posterior pelvic ring was in 28 patients, fractures of iliac and sacral bones – in 15.

Figure 2. X-ray images of the patient I., age of 27, a pelvic ring injury 61-B2: a) at admission; b) after reconstruction of the anterior complex of the pelvis with use of EFD; c) after fixation of the posterior pelvic complex with 7.3 mm screw

    

58 patients additionally received the anterior complex osteosynthesis with plates and screws. Among them, opened injuries were in 6 (10.3 %) patients and were presented by urinary bladder laceration in 4 cases, urethra laceration – in 2. 17 patients had injuries of B type, 41 – C type, unilateral – 24, bilateral – 34. 50 patients had pubic symphysis, 8 – fractures of branches of pubic bones. Among 50 patients with pubic symphysis rupture, 14 patients had injuries to the posterior complex of B type, 36 – C type. SIJ lacerations as the main injury to the posterior complex of the pelvic ring were in 37, sacral and iliac fractures – 21.
In case of lacerations of pubic symphysis, we used plate osteosynthesis (Fig. 3), for fractures of the pubic bone – fixation was conducted with screws in most cases (Fig. 4). The indication was type B2 pelvic ring injuries from lateral compression or C type from shift or combined impacts.

Figure 3. X-ray images of the patient A., age of 48, a pelvic ring injury 61-B3: a) at admission, with cystography; b) after application of pelvic forceps; c) after final reconstruction of the anterior pelvic semi-ring with the plate; the posterior semi-ring was fixed with 7.3 mm screws

     

Figure 4. X-ray images and computer 3D reconstruction of the pelvis of the patient K., age of 19, a pelvic ring injury 61-B2: a) pelvic X-ray image before surgery; b) X-ray image after screw fixation for anterior and posterior pelvis; c) pelvic 3D reconstruction before surgery; d) 3D pelvic reconstruction after fixation of anterior and posterior complexes

       

Estimation of the results considered the patterns of complications and treatment results. The analysis of the data was initiated from construction of the frequency diagram. Me and interquartile range were estimated. χ2 test with Yates’ correction and Bonferroni’s technique with multiple comparisons were used for estimation of statistical significance of differences. The critical level of significance was less than 0.05 in testing the null hypotheses [21].
The study was conducted in compliance with the ethical principles of World Medical Association Declaration of Helsinki – Ethical Principles for Medical Research Involving Human Subjects, 2013, and the Rules for clinical practice in the Russian Federation (the Order of Russian Health Ministry, 19 June 2003, No.266) with receiving the patients’ agreement for participation in the study and approval from the local ethical committee. 

RESULTS AND DISCUSSION

3 (1 %) patients died. The causes of death were pulmonary embolism in the first case, bleeding from gastric stress ulcer in the second case and sepsis in the third case. The lethal outcomes were not associated with surgical interventions for the pelvic ring and were the consequences of complications of the severe PT.
There were 155 somatic complications in 105 (35.4 %) patients. The table 1 shows their patterns and the incidence. Deep venous thrombosis in the lower extremities was the most common, less frequently – bronchopulmonary and abdominal complications, bedsores, sepsis and others.

Table 1. Characteristics and incidence of somatic complications (n = 297)

Type of complications

Abs. number

%

Deep venous thrombosis in lower extremities

77

49.7

Pneumonia, pleuritis

47

30.3

Bedsores

15

9.8

Abdominal complications

7

4.5

Sepsis

3

1.9

Multiple organ dysfunction

3

1.9

Gastric stress-ulcers

2

1.3

PE

1

0.6

TOTAL

155

100


Most somatic complications were identified in the patients with PT severity > 25 according to ISS, with severe TBI, thoracic or abdominal injuries. 57 (54.3 %) patients had a bilateral unstable injury to the pelvic ring (type C), 61 (58.1 %) – a dominating injury to the ligamentous apparatus of the posterior pelvic semi-ring.
There were 63 local complications in 41 (13.8 %) patients. The table 2 shows the characteristics and the incidence. Peripheral neurological disorders were the most common and were presented by injuries to lumbosacral junction roots in 11 patients, fibular nerve lesions – in 10, sciatic nerve lesions – in 9. In all cases, the signs of neurological deficiency were immediately after trauma and were its consequences. The patients received the complex of conservative treatment. Within one and a half year, the full recovery of the function was achieved in 21 patients, improvement – in 9. The patients with improvement did not show any motional neurological deficiency and had only in skin sensitivity disorders.

Table 2. Characteristics and incidence of local complications (n = 297)

Complications

Amount

%

Neurologic disorders

30

46.9

Hematoma inflammation in pelvic region

11

17.2

Postsurgical wound complications

11

17.2

Migration and fractures of constructs

8

12.5

Secondary displacements

4

6.2

TOTAL

64

100


Hematoma inflammation in the pelvic region was in 11 patients. Among them, ISS > 25 was in 9, type B pelvic ring injuries – in 6, type C – 5, unilateral – 3, bilateral – 8. A dominating injury to the bone component of the posterior semi-ring was in 8 patients, the ligamentous component – in 3. 4 patients had pubic symphysis lacerations, 7 – bone fractures in the anterior semi-ring. All patients received opening and draining of hematomas and secondary tension healing.
The inflammation of postsurgical wounds was in 11 patients. Among them, ISS > 25 was in 7, type B pelvic ring injuries – in 8, type C – in 3, unilateral – in 5, bilateral – in 6, a dominating injury to the bone component of the posterior semi-ring – in 8, the ligamentous one – in 3. 8 patients had pubic symphysis lacerations, 3 – bone fractures in the anterior semi-ring. Opened fractures were in 3, closed – in 8. The signs of inflammation were identified on the days 4-7 after surgery. 7 patients experienced postsurgical wound inflammation in the region of the anterior pelvic semi-ring after plate osteosynthesis for pubic symphysis, including 3 patients with opened injuries (urinary bladder lacerations). 4 inflammatory events appeared in the region of the posterior pelvic semi-ring, in the place of positioning of cannulated screws fixing SIJ. Moreover, all patients had unstable metal constructs. Inflammatory foci sanitation was conducted in all cases. Additional stabilization of the pelvic ring with EF was in 4 cases.
Migration and fracture of constructs were identified in 8 patients. Among them, ISS > 25 was in 5, type B injuries – in 2, type C – in 6, unilateral – in 2, bilateral – in 8, a dominating injury to the bone component of the posterior semi-ring – 2, the ligamentous one – 6. 6 patients had the pubic symphysis lacerations, fractures in the anterior semi-ring – in 2.
3 patients with the pubic symphysis laceration had the migration and a fracture of the constructs in the anterior pelvic semi-ring, 2 patients – displacement in the posterior pelvic structures, 1 – hemipelvis reluxation, 2 – unstable posterior complex. 3 patients with migration and fractures of screws in the region of the plate on the pubic, two patients had type C pelvic injuries, one – type B. All injuries were bilateral, with the unstable posterior complex through SIJ lacerations. Migration of fractures of screws was identified within 1.5-2 months in control follow-up. All patients had the excessive body mass. The constructs were removed. 3 patients with secondary displacements required for recurrent fixation of the pelvic ring with the anterior frame of EF and remounting of migrated screws to the posterior complex. One patient received the conservative treatment.
Local complications were more often in patients with ISS > 25, with unstable and bilateral injuries to the posterior semi-ring, with a dominating injury to the ligamentous apparatus of both anterior and posterior pelvic semi-ring and in patients with excessive body mass.
Within 3-12 years after hospital discharge, 152 persons with cannulated screws were examined (51.2 % of the primary group). There were 83 men (54.6 %) and 69 women (45.4 %).
Meijid score results were [22]: excellent – 63 (41.4 %), good – 44 (28.9 %), satisfactory – 39 (25.7 %), poor – 6 (3.9 %). The poor outcomes were determined by pain in the pelvic region and during walking, and by need for additional supporting during long term physical load. 4 of 6 patients with poor outcomes of treatment had the vertical displacement (more than 2 cm) in the posterior pelvic semi-ring and intense pain syndrome. 4 patients with posttraumatic deformations of the pelvic ring had a relative shortening of the extremities, resulting in claudication, need for obligatory use of additional supporting and shortening correction with orthopedic footwear. Among them, 2 had some persistent root disorders in view of flaccid paralysis of one branch of the fibular nerve on the side of hemipelvis displacement.
The poor treatment outcomes were identified in patients with complete injuries to the pelvic ring of C type through sacral fractures with displacement of a half of the pelvic upwards and posteriorly. According to our opinion, treatment of such injuries with MIO and iliosacral screws is difficult and even impossible in most cases. Firstly, there are some difficulties of closed reposition with displacement of sacral fragments. Secondly, a zone for fixation of the threading part of the screw in the sacrum is limited, resulting in loosening and migration of screws in mobilization of patients, especially in a bilateral injury. Thirdly, “safe” active mobilization of patients requires for prolongation of bed rest, up to primary union of a sacral fracture that is unacceptable in PT.
Considering this fact, such injuries require for other approach to treatment – creation of the additional third supporting point on the spine – distant spinal and pelvic fixation. The figures 5 and 6 show an example of use of this technique.

Figure 5. The patient T., age of 45, a pelvic injury 61-C3, bilateral transsacral instability, displacement of the left hemi-pelvis upwards: a) pelvic X-ray image at admission; b) after temporary fixation with EFD; c) X-ray image after plate fixation of anterior pelvic semi-ring, and posterior semi-ring – with screws with screw migration and recurrent displacement of hemi-pelvis; d) horizontal CT image; e) X-ray image after removal of metal constructs; f) horizontal CT image

           

Figure 6. The patient T., age of 45, a pelvic ring injury 61-C3: X-ray images after lumboiliac fixation with augmentation screws, left-sided displacement of hemi-pelvis was corrected

   


Among patients with satisfactory outcomes, the residual vertical displacement was within 1 cm with ectad rotation about 10-15 degrees in 9 persons. However it did not cause any inconvenience for the patients.
The analysis of health-related life quality was estimated with MOSSF-36 [23]. The results are presented in the table 3. As the table shows, the patients had a relatively high physical and life activity with sufficient level of social communication. They showed high psychoemotional background with low pain syndrome.

 

CONCLUSION

Therefore, the analysis of the results of treatment of pelvic ring injuries in patients with PT with use of MIO for posterior semi-ring with transcutaneous iliosacral cannulated screws showed that:
- the highest amount of complications was noted in patients with unstable bilateral injuries to the posterior semi-ring with a dominating injury to the ligamentous apparatus;
- transsympheseal and transpubic instability in displacement > 2.5 cm required for additional stabilization of the anterior pelvic semi-ring;
- EF is the most optimal for opened injuries, B1 injuries and as additional measure for pelvic ring fixation in obese patients;
- the use of plate osteosynthesis of the anterior semi-ring is possible for all types of closed injuries. Screws for fixation of the anterior complex are indicated for B2 fractures and for urinary tract injuries in patients with type C injuries and fractures of pubic bones;
- during pelvic reconstruction in horizontal or rotational instability, first of all, reposition and fixation of the anterior semi-ring and then the posterior one are conducted; and, conversely, for vertical instability or displacement in the posterior semi-ring;
- presence of an opened pelvic ring fracture is not an obstacle to transcutaneous iliosacral cannulated screws for stabilization of the posterior complex of the pelvic ring;
- vertical displaced fractures of the sacrum requires for distant spinal and pelvic fixation in most cases. 

Information on financing and conflict of interests

The study was conducted without sponsorship.
The authors declare the absence of any clear or potential conflicts of interests relating to publication of this article.

REFERENCES:

1.      Hak DJ, Smith WR, Suzuki T. Management of hemorrhage in life-threatening pelvic fracture. Am Acad Orthop Surg. 2009; (17): 447-457
2.      Ruchholtz S, Lefering R, Paffrath T, Oestern HJ, Neugebauer E, Nast-Kolb D et al. Reduction in mortality of severely injured patients in Germany. Dtsch Arztebl Int. 2008; 105(13): 225-231
3.      Smith WR, Ziran BH, Morgan SJ. Fractures of the pelvis and acetabulum. New York: Informa Healthcare USA. Inc., 2007. 359 p.
4.      Kazantsev AB, Ter-Grigoryan SM, Putyanin SM, et al. Long-term results of surgical treatment of patients with pelvic injuries. In: Materials All-Russian conference dedicated to the 50th anniversary of AO/ASIF. M., 2008; 56 p. Russian (Казанцев А.Б., Тер-Григорян С.М., Путятин С.М. и др. Отдаленные результаты хирургического лечения больных с повреждениями таза //Материалы Всероссийской конференции, посвященной 50-летию AO/ASIF. М., 2008. С. 56)
5.      Suzuki T, Shindo M, Soma K, Minehara H, Nakamura K, Uchino M, Itoman M. Long-term functional outcome after unstable pelvic ring fracture. Trauma. 2007; (63): 884-888
6.      Montgomery KD, Geerts WH, Potter HG, Helfet DLThromboembolic complications in patients with pelvic trauma. Clin Orthop. 1996; (329): 68-87
7.      Kurshakova IV, Bagdasaryants VG. Neurological complications of pelvic fractures. In: High technologies in medicine: the materials of scientific practical conference dedicated to 15th anniversary of Regional Clinical Center of Miners’ Health Protection, September 11-12, 2008. Siberian Department of RAMS; Regional Clinical Center of Miners’ Health Protection. Novosibirsk: Izdatel, 2008; 91-92. Russian (Куршакова И.В., Багдасарянц В.Г. Неврологические осложнения переломов костей таза //Высокие технологии в медицине: материалы Всероссийской научно-практической конференции, посвященной 15-летию ФГЛПУ «НКЦОЗШ», 11-12 сентября 2008 г. /СО РАМН; ФГЛПУ «НКЦОЗШ». – Новосибирск: Издатель, 2008. – С. 91-92)
8.      Aghazhanyan VV. Polytrauma: problems and practical questions. Polytrauma. 2006; (1): 5-8. Russian (Агаджанян В.В. Политравма: проблемы и практические вопросы //Политравма. 2006. № 1. С. 5-8)
9.      Milyukov AYu. Formation of tactics of treatment of victims with injuries of the pelvis. Polytrauma. 2013; (3): 22-29. Russian (Милюков А.Ю. Формирование тактики лечения пострадавших с повреждениями таза //Политравма. 2013. № 3. С. 22-29)
10.    Agadzhanyan VV, Pronskikh AA, Ustyantseva IM, Agalaryan AKh, Kravtsov SA, Krylov YuM et al. Polytrauma. Novosibirsk: Nauka Publ., 2003. 494 p. Russian (Агаджанян В.В., Пронских А.А., Устьянцева И.М., Агаларян А.Х., Кравцов С.А., Крылов Ю.М. и др. Политравма. Новосибирск: Наука, 2003. 494 с.)
11.    Sokolov VA. Multiple and associated injuries. Moscow: GEOTAR-Media, 2006. 512 p. Russian (Соколов В.А. Множественные и сочетанные травмы. М.: ГЭОТАР-Медиа, 2006. 512 с.)
12.    Ruedi TP, Buckley RE, Moran CG. AO Principles of Fracture Management. Vol. 2. New York, 2007. P. 556-1103
13.    Tile M, Halfet DL, Kellam JF. Fractures of the pelvis and acetabulum. Philadelphia: Lippincott Willams & Wilkins, 2003. 830 p.
14.    Matta JM, Saucedo T. Internal fixation of pelvic ring fractures. Clin. Orthop. Relat. Res. 1989; (242): 83-97
15.    Bondarenko AV, Smaznev KV, Bogdanova ТА. Use of cannulated screws for osteosynthesis of pelvic and acetabulum injuries in patients with polytrauma. Polytrauma. 2008; (1): 19-23. Russian (Бондаренко А.В., Смазнев К.В., Богданова Т.А. Использование канюлированных винтов при остеосинтезе повреждений таза и вертлужной впадины у пациентов с политравмой //Политравма. 2008. № 1. С. 19-23)
16.    Bondarenko AV, Kruglykhin IV, Voitenko AN. Use of cannulated screws in surgery for pelvic injuries. Herald of Traumatology and Orthopedics. 2016; (2): 25-34. Russian (Бондаренко А.В., Круглыхин И.В., Войтенко А.Н. Использование канюлированных винтов в хирургии повреждений таза //Вестник травматологии и ортопедии. 2016. № 2. С. 25-34)
17.    Mosheff R. Percutaneous fixation of fractures of the pelvic ring and acetabulum. Margo Anterior. 2009; (2): 7-10. Russian (Мошефф Р. Перкутанная фиксация переломов тазового кольца и вертлужной впадины //MargoAnterior. 2009. № 2. С. 7-10)
18.    Lazarev AF, Solod EI. Percutaneous fixation of acetabular fractures. In: Osteosynthesis and endoprosthetics: abstracts of International Pirogov Scientific Practical Conference, May 16-18, 2008. Moscow. M., 2008; 117 p. Russian (Лазарев А.Ф., Солод Э.И. Перкутанный остеосинтез переломов вертлужной впадины //Остеосинтез и эндопротезирование: тезисы докладов Международной Пироговской научно-практической конференции, 15-16 мая 2008 г., г. Москва. М., 2008. С. 117)
19.    Baker SP, O'Neill B, Haddon W Jr, Long WB. The Injury Severity Score: a method for describing patients with multiple injuries and evaluating emergency care. J. Trauma. 1974; 14(3): 187-196
20.    UCF. Universal classification of fractures /Maurice E. Müller Foundation in cooperation documentation center AO-ASIF. M., 1996. Bookletnumber 2. 32 p. Russian (УКП. Универсальная классификация переломов /Фонд Мориса Е. Мюллера при сотрудничестве центра документации AO-ASIF. М., 1996. Буклет № 2. 32 с.)
21.    Glants S. Medico-biological statistics: translation from the Eng. M.: Practice, 1998. 459 p. Russian (Гланц С. Медико-биологическая статистика: пер. с англ. М.: Практика, 1998. 459 с.)
22.    Majeed SA. Grading the outcome of pelvic fractures. J. Bone Joint Surg. 1989; 71B(2): 304-306
23.    Hygienic assessment and normative values of the quality of life indicators of adolescents studying in different types of educational institutions, according to the MOSSF-36 questionnaire. Guidelines. Approved by the Plenum of the Scientific Council on Hygiene and Health of Children and Adolescents on October 3, 2012 (Protocol No.14). 2012.; 30p. Russian (Гигиеническая оценка и нормативные величины показателей качества жизни подростков, обучающихся в разных типах образовательных учреждений, по данным опросника MOSSF-36. Методические рекомендации. Одобрены Пленумом Научного совета по гигиене и охране здоровья детей и подростков 3 октября 2012 г. (протокол № 14). 2012. 30 с.)

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