Bone Block Formation in Application of Biositall Grafts for Treatment of Traumas and Diseases of the Spine: A Process Description

Orlov V.P., Dulaev A.K.

Medicomilitary Academy, Saint Petersburg, Russia

Treatment of patients with traumas and diseases of the spine is still an urgent problem of modern neurosurgery, traumatology and orthopedics. The last years are characterized by a tendency towards increase of a portion of surgical technologies among methods of treating patients with spinal pathology [11, 12, 18].

The most important elements of surgical treatment of such cases include reconstruction of supporting structures, affected by a pathologic process, and reliable stabilization of a spinal column in a proper position, permitting to achieve effective restoration of lost functions at an early stage [4, 5, 12]. So far the main method of reconstruction of such structures is anterior spondylodesis with partial or complete substitution of an affected vertebral body [6, 7, 10].

Neurosurgeons and traumatologists-orthopedists use bone auto- or allografts in the majority of cases. However, in spite of many evident advantages, bone auto- and alloplasty has several considerable drawbacks. It makes many specialists search for alternative methods of restoring a supporting function of the spine. According to the majority of researchers, these drawbacks include a traumatic character of operations for obtaining autografts; frequent necessity to take autografts from several donor areas, which can be connected with appearance of cosmetic defects and a risk of infectious complications; difficulties, conditioned by preparing, storing and transporting allografts and their possible contamination with viruses (AIDS, etc.); responses, caused by tissue incompatibility; progression of spinal deformities due to loss of mechanical properties of auto- and allografts [3, 4, 12-14, 17].

Thus, use of biocompatible artificial materials in reconstructive-restorative operations on the spine acquires greater importance. Grafts of ceramics, biopolymers, metals, carbon-containing and composite materials have been introduced into clinical practice. Physical-chemical biological properties of an artificial material, substituting a bone, are to be close to those of normal bone tissue. It is to be osteocompatible and to promote an optimum course of reparative processes [1, 2, 8]. At present, biodegrading substituting materials, based on natural polymers (Bioss, Interpos, Osteo-Set) are widely used in clinical practice. However, a granulated form of these materials does not allow to get a full-value restoration of supporting structures of vertebral bodies and their high cost limits their use in our country to a considerable extent [9]. Specialists of the Saint Petersburg Technologic Institute, participating in the Biositall Federal Program, have managed to obtain prospective samples of grafts for substituting defects of bone tissue of vertebral bodies. Biological properties and possible use of these materials in clinical practice have not been studied.

The Research Goal

Development and introduction of new reconstructive-restorative operations with applying proposed grafts in patients with spinal traumas and diseases.

Material and Methods

Biositall grafts were subject to clinical trial and used for substituting defects of vertebral bodies in trauma (82 cases) and spinal diseases (39 cases). There were 82 male (67.8%) and 39 female (32.2%) patients. All casualties and patients (121 men) were divided into 3 groups according to a graft type, used for performing anterior spondylodesis: group 1 - an autograft, group 2 - a biositall graft, group 3 - an autograft+biositall (Fig.1).

There were 2 subgroups in group 1; they comprised cases with plasty by an autograft, taken from ribs and from the upper flaring portion of the ilium respectively. Patients and casualties of groups 2 and 3 were subdivided into two subgroups as well. Thus, group 2 consisted of cases with low-porosity biositall grafts (N 216) and porous biositall grafts (M-12 and M-31); the first subgroup of group 3 included cases with combined plasty by an autograft and low-porosity biositall, the second subgroup consisted of patients with plasty by an autograft and porous biositall.

As for group 1 (49 cases), autografts, taken from ribs and the upper flaring portion of the ilium were used in 18 (the first subgroup) and 31 (the second subgroup) patients respectively.

Plasty of vertebral bodies with application of biositall was performed in 72 cases (59.6%): biositall proper was applied in 37 patients (51.4%, group 2) and combined plasty was made in 35 cases (48.6%, group 3).

Low-porosity biositall N 216 and porous M-12 and M-31 biositalls were used for performing anterior spodylodesis in 10 (13.9%), 19 (26.4%) and 43 (59.7%) cases respectively. Plasty of defects of vertebral bodies by low-porosity and porous biositalls was made in 3 (8.1%) and 34 (91.9%) of patients of group 2. Combined plasty in patients and casualties of group 3 was used only in defects of thoracic and lumbar spine; distribution of low-porosity and porous biositalls was as follows: 7 patients (20.0%, the first subgroup) and 28 cases (80.0%, the second subgroup). Low-porosity grafts were applied mainly in traumas of vertebral bodies. Usually plasty of bone defects in spinal diseases was performed with porous grafts (M-12 and M-31). Efficacy of treatment was estimated on the basis of such criteria, as dynamics of a neurologic state, a period and character of formation of an anterior bone and bone-biositall block, a volume of intraoperative correction of spinal deformity and preservation of an obtained result during all the period of formation of a bone and bone-biositall block, a rate and character of postoperative complications, anatomic-functional results by the end of a rehabilitation period. Long-term observation lasted 6-8 months on the average.

Data processing, parameters of descriptive statistics (M, s2, m, percent distribution, etc.), reliability of difference of indices in groups with calculation of Student's t-criterion and c2 were estimated with the help of Microsoft Windows software (Microsoft Excel, Ver. 7.0). Difference was considered to be reliable in p<0.05.

Results

A number of cases with traumas of the spine and spinal cord (TSSC), operated in Clinics of Neurosurgery and Military Traumatology and Orthopedics of the Medicomilitary Academy in 1994-2000, was equal to 82. There were 26 females (37.1%) and 56 males (68.3%). A mean age was 33.7±2.7 .

The most frequent cause of spinal trauma was car accidents and falling from a considerable height (22.4% and 48.8% respectively). Isolated injuries of the spine were watched in 61.0% of cases. Associated and multiple spinal injuries accounted for 39% (n=32) of all types of trauma. Associated injuries of extremities (14.7%) and a head (3.7%) were prevalent. Traumatic shock of different severity was observed in 14.6% of admitted casualties. Trauma of the cervical, thoracic and lumbar spine was present in 24 (29.3%), 22 (26.8%) and 36 (43.9%) cases respectively. Fractures of one vertebra (67.0%) were more frequent in comparison with fractures of two vertebrae (29.5%).

Distribution of patients, based on assessing severity of neurologic disorders according to classification of Frankel H.L. et al. [15], was as follows (Table 1).

Table 1

Distribution of Patients with Spinal Injuries.

Type A

Type

Type

Type D

Type

%

n

%

n

%

n

%

n

%

n

9.7

8

4.8

4

7.4

6

35.4

29

42.7

35

Operations were made within 10-20 days. Decompression of the vertebral canal was performed in all cases with complicated spinal trauma. Anterior spondylodesis was done in 24 patients with injuries of the cervical spine. Corporodesis with application of biositall (group 2) was performed in 13 cases (54.2%); porous M-12 and M-31 grafts and a low-porosity biositall implant (N 216) were used in 12 (92.3%) and 1 (7.7%) out of these patients respectively. As for group 1, corporodesis was made with the help of a cortical-spongy free autograft, taken from the upper flaring portion of the ilium.

Regress of neurologic symptoms was watched in 16 (84.2%) out of 19 cases with complicated TSSC during the first two weeks of a postoperative period; it became more marked later.

All the cases with anterior spondylodesis demonstrated no rejection response, bone tissue necrosis, wound suppuration and graft destruction during a period of formation of a bone-biositall block.

Its formation took place on a graft-bone borderline. Data of spiral CT-densitometry were indicative of higher density of bone tissue on the borderline with a graft, i.e. there appeared areas of sclerosis. An analogous response of a bone bed was watched in autotransplantation. One could see a reliable bone-biositall block and dense graft margins on the borderline with a bone bed 10-12 months later (Fig.2).

The analysis of efficacy of spinal deformity correction and its preservation during a period of formation of a ventral bone block in cervical trauma was carried out in parallel with the analysis of two groups of cases. Ventral spondylodesis in group 1 (n=11) was performed with application of cortical-spongy autografts. In spite of their peculiarities, correction loss was observed in 2 patients; it was not more, than 5-6o. There was no considerable loss of correction in group 2 (n=13); only 2 cases had prominence of a graft into a vertebral body, whose value did not exceed 1-1.5 mm. Correction loss in one case was equal to 6o.

There were 4 complications in group 1; three of them were connected with a place, from which a cortical-spongy graft was taken. One patient developed seroma and a wound was not sutured; it resulted in increase of a treatment period. There was pain in the area, from which an autograft was taken, in 2 cases; it was conditioned by compression of branches of sensitive cutaneous nerves by ligature. One patient had a fibrous block (Fig.3).

There was one complication in group 2. It was connected with development of posttraumatic osteochondrosis with radicular syndrome, which appeared two years later; there was regression of pain syndrome after conservative treatment. An average period of stay in hospital in groups 1 and 2 was equal to 16± and 12±2 days respectively. There were no fatal outcomes in both groups. External fixation of the cervical spine in both groups was preserved during 3.5-4 months.

Functional results of treatment were estimated at the end of a rehabilitation period (12-18 months later). Two patients from group 1 had considerable limitation of movements, conditioned by progressive osteochondrosis of the cervical spine. Restoration of a supporting function of the spine was achieved in 12 cases from group 2. One patient had limitation of active movements and tenderness, which developed two years later (sequlae of dislocation fracture of the C2 vertebra), but a volume of movements restored almost fully after the second course of rehabilitation and there was pain regression.

All patients with traumas of the thoracic and lumbar spine (n=58) underwent anterior spondylodesis.

Efficacy of surgical treatment was estimated on the basis of the same criteria, which were used in trauma of the cervical spine. A period of observation varied from 1 up to 5 years.

Characterizing dynamics of neurologic disorders, one should mention, that anterior decompression of the spinal cord and roots of the horse's tail was less effective in patients with sequelae of complicated TSSC, as it was accompanied by long-term compression of neural structures of the vertebral canal.

Complete and partial regression of neurologic symptoms after surgical treatment was watched in 12 (42.9%) and 3 (10.7%) out of 28 cases with complicated TSSC respectively. Positive dynamics in a neurologic state was seen in 15 patients (53.6%); there was no marked positive dynamics in 13 cases (46.4%). Such results can be explained by the following fact: 18 (64.2%) out of 28 patients, delivered to Clinics of Neurosurgery and Military Traumatology and Orthopedics, were hospitalized within 10-40 days since the moment of sustaining TSSC.

Anterior spondylodesis in group 1 (n=23) was performed with an autograft: fragments of ribs and upper flaring portion of the ilium were used in 15 (65.2%) and 8 (34.8%) cases respectively. Formation of a ventral bone block took place under conditions of complete or almost complete elimination of deformity with providing a good contact between a graft and bone bed. Dynamics of autograft integration within a bone bed was identical to that, watched in plasty of defects of vertebral bodies in the cervical spine. Formation of a bone block and processes of its remodeling started within 3-6 months and continued during 1-2 years (Fig.4).

In combined plasty a picture of a bone block formation in group 3 was practically analogous to that, described above. However, a period of its formation was 7-10 months. As a rule, we used porous grafts (M-12 and M-31) in combined plasty. One more peculiarity of combined plasty of vertebral bodies consisted in the following: an implant had a supporting function during a period of remodeling of a bone autograft with no or insignificant correction loss (Fig.5).

While analyzing efficacy of correction of the vertebral column deformities in spinal trauma, we compared two groups of patients. Internal correction and stabilization of the spine with the help of different structures was performed in both groups. A value of residual deformity of the spine was estimated according to J.R. Cobb [16].

Effective correction of the spine deformity was achieved only in case of "fresh" injuries by means of one-stage reposition, performed on an operating table. Correction efficacy in intermediate and late periods of spinal trauma was determined by a character of a pathologic process, deformation rigidity, a degree of surgical mobilization of the spine, as well as by a method, used for internal correction and fixation of the spine with metal grafts. Use of modern systems of anterior Z-plate and posterior (transpedicular and multi-hook laminar systems) correction and fixation allowed to eliminate or minimize (up to permissible values) deformities of the spine in 94.7% of cases in an acute period of TSSC and in 84.1% of patients with trauma sequelae. Defective consolidation, manifesting itself in the form of a bone-fibrous block was watched in 5 patients of group 1 (21.7%), the rest cases had a reliable bone block. There was a reliable bone-biositall block in all 28 patients of group 3, who underwent combined plasty of vertebral bodies. At the same time there was no bone-biositall block in 1 (2.7%) out of 3 cases of group 2 (the first subgroup) with plasty of vertebral bodies by biositall N 216.

Correction loss in anterior spondylodesis (irrespective of a plasty type), combined with application of modern systems (transpedicular, multi-hook laminar fixation), did not exceed 10o. It should be noted, that these patients did not complain of pain in the spine on discharge and later. Use of CITO plates (Central Institute of Traumatology and Orthopedics), wire, metal rods and tightening devices resulted in correction loss of more than 20o, depending on a type of pathology and peculiarities of surgical intervention.

Thus, residual kyphotic deformity of the spine on discharge varied from 11o up to 29o and was watched in 6 cases of group 1 and 2 patients of groups 2 and 3. Dynamics of posttraumatic kyphotic deformity of the thoracic and lumbar spine in different groups is presented in Table 2.

Table 2

Dynamics of Posttraumatic Kyphotic Deformity of the Thoracic and Lumbar Spine after Surgical Treatment.

Injury Localization

Mean Values of Posttraumatic Kyphotic Deformity (Degrees)

 

Primary spondylograms

Control spondylograms

The thoracic spine (n=22)

18.5±4.3

5.2±3.1

The lumbar spine (n=36)

15.2±2.6

4.3±1.3

Mean values

17.6±3.3

6.5±1.7

The data, given in Table 2, show, that surgical treatment of primary kyphotic deformities in patients of all groups resulted in considerable correction (approximately by 10o), which had a positive effect on functional outcomes.

Use of modern methods of surgical treatment in combination with new types of internal fixation of the spine allowed to achieve good restoration of its supporting function. There were no static disorders at the moment of final examination in 43 cases (74.1%); moderate and minor disorders were watched in 3 (5.1%) and 12 (20.6%) patients respectively.

Rehabilitation of the majority of cases included 3 stages. The first stage took place in hospital. As for the second and third stages, they were carried out in a rehabilitation inpatient center (hospital N 40, Sestroretsk) and a polyclinic under supervision of its doctors (Fig.6).

A mortality rate was 1.7% (1 case). A fatal outcome was caused by thromboembolism of the pulmonary artery in the nearest postoperative period (2 weeks after operation).

All errors and complications were divided into intraoperative and postoperative. The most spread intraoperative errors were represented by imperfect placement of metal constructions (5 cases). There were 2 patients with pneumonia, which developed after thoracotomy in a postoperative period, It regressed after treatment with antibiotics; 2 cases had suppuration of a postoperative wound. One patient developed osteomyelitis of the upper flaring portion of the ilium in the area, from which an autograft for combined plasty of a vertebral body was taken.

Anterior spondylodesis with application of autografts was performed in 11 patients (45.8%) of group 1 and 13 cases (54.2%) of group 2, who had degenerative-dystrophic diseases of the cervical spine. Low-porosity grafts were not used with this purpose. Porous M-12 and M-31 biositalls were applied in 5 and 9 patients of the above groups respectively. Neurologic examination served the basis for dividing these cases in accordance with three clinical forms of a disease course: A - patients with a radicular form (10 men), who had symptoms, indicative of radiculopathy, or monosegmental disorders; B - patients with a medullary form of a disease (6 men) and conduction disorders; C - cases with a mixed radicular-medullary form (8 men) and a combination of the above-mentioned symptoms.

All 24 patients were operated. Performing anterior spondylodesis, we used a biositall graft in 13 patients (group 2); a cortical-spongy autograft, taken from the upper flaring portion of the ilium, was applied in 11 cases (group 1) (Fig.7).

Dynamics of neurologic symptoms in both groups was estimated in a postoperative period (Table 3).

Table 3

Dynamics of Neurologic Symptoms in a Postoperative Period: Clinical Estimation.

Results

After Operation

After 3 Months

After a Year

  A Medullary Form

 

 

 

Good

3

3

3

Satisfactory

2

2

2

Poor

1

1

1

  A Radicular Form

 

 

 

Good

9

9

10

Satisfactory

1

-

-

Poor

-

-

-

  A Radicular-Medullary Form

 

 

 

Good

4

4

4

Satisfactory

3

3

3

Poor

1

1

1

Formation of a good bone and bone-biositall block without considerable loss of obtained intraoperative correction was watched in all cases of group 1 (an autograft) and group 2 (a biositall graft). Collapse of intervertebral spaces and graft migration were absent (Fig.8), (Fig.9), (Fig.10).

Treatment of 8 patients with non-specific spondylitis was carried out in the Clinic of Military Traumatology and Orthopedics.

Plasty of vertebral bodies with an autograft was performed in 2 cases (25.0%) of group 1; combined plasty was used in 6 patients (75.0%) of group 3.

A low-porosity graft (biositall N 216) was applied in combined plasty in 1 case. Porous M-12 and M-31 biosotalls were implanted to 2 and 3 patients respectively.

A pathologic process was localized in the lumbar spine in 3 patients; it was watched in the thoracic spine in 3 cases as well. Two adjacent vertebrae were involved into an inflammatory process in 4 cases. An infecting agent (Staphylococcus aureus) spread via blood in all patients. A pathologic fracture of vertebral bodies in the thoracic spine was watched in 2 cases. Unfortunately, late diagnosis and diagnostic mistakes, made during examination, were typical of all cases. There were three stages of treatment in an acute and subacute course of the disease.

The first stage was aimed at arresting acute inflammatory manifestations and delimitation of a suppurative process. It was achieved by long-term (5-6 weeks) IV administration of antimicrobial drugs of the fluorochinolon group (Tarivid, Ofloxacin, Ciprofloxacine) in a dose of 0.2 g twice a day. Isolation of an infecting agent and estimation of its sensitivity to antibiotics was followed by specific treatment with prescription of mean therapeutic doses.

The second stage was represented by surgical treatment proper. It consisted in two consecutive interventions on posterior and anterior segments of the spine, which were performed with an interval of 15-25 days. Hook systems of stabilization were used for posterior internal correction and fixation. Antibacterial treatment was carried out at the third stage (a postoperative period). Drugs were administered intravenously during 10-14 days; then they were taken per os during a month (Fig.11).

Anterior spondylodesis in non-specific spondylitis led to formation of strong bone (n=2) and bone-biositall blocks (n=5).

Combined plasty of vertebral bodies with biositall N 216 and an autograft of rib fragments resulted in complication in 1 patient. He developed fistula with serous discharge two years later. The patient was operated and an implant was removed. Autografts promoted formation of a bone block. The long-term observation (5 year) showed, that there were no disorders of a supporting function of the spine and static properties, as well as recurrences in all patients.

Surgical treatment of 5 cases with tumors of the spine and roots of the horse's tail was carried out in Clinic of Neurosurgery. Plasty of defects of vertebral bodies by an autograft was performed in 2 patients (group 1): they were taken from the upper flaring portion of the ilium (1 case, the cervical spine) and ribs (1 case, the lumbar spine). Corporodesis with a porous biositall graft was performed in 3 patients (group 2) after tumor removal.

Chondrosarcoma was localized in the cervical spine in 2 cases (Fig.12), (Fig.14). Osteochondroma in the lumbar spine was diagnosed at the level of L2 (1) and L4 (1) in 2 patients (Fig.13), (Fig.15). Neurinoma of the horse's tail roots with a pathologic fracture of L1 was watched in 1 female.

Dynamics of a neurologic state was estimated with the help of the ASIA/IMSOP classification. There were no marked neurologic disorders of the A type. The C type disorders were present in 1 female patient with neurinoma of the horse's tail roots. The D type disorders were watched in 2 cases with chondrosarcoma of the cervical spine and osteochondroma of L4 vertebra. We failed to reveal any neurologic disorders in 2 patients (the E type).

A reliable bone and bone-biositall block was formed after operation in all cases. Remodeling of an autograft resulted in kyphosis of 15o, which appeared in 1 case (group 1) at the level of the lumbar spine 6 months later. There was no relapse of tumor in a long-term period (4 years)

X-ray examinations and spiral CT with densitometry (group 1, n=49) made it possible to study a process of formation of a bone block in application of bone autografts in different segments of the spine. It was conditionally divided into 3 consecutive periods: revascularization (2-4 months), resorption (6-8 months), remodeling and formation of a bone block (8-16 months).

X-ray findings during the first period showed loss of clearness of the transplanted bone outlines with uneven and indistinct areas at its ends. There was a lucid streak of 1 mm between an autograft and a bone bed, which disappeared 3-4 months later. Spiral CT-densitometry demonstrated increase of density of bone tissue in vertebral bodied around grafts. These changes were observed in 3.7±2.4 months after operation (Fig.16).

The second period (a period of active remodeling) was characterized by more indistinct and uneven outlines of a graft butt-end; it was especially typical of areas of its close contact with a bone. These changes were more marked in remodeling of cortical- spongy bone autografts. Ends of a graft merged with a shadow of vertebral bodies in some places of this zone; there were some areas with longitudinal trabeculae. X-ray examination revealed a good contact between an autograft and bone bed; one could watch fragmentation of grafts in some cases. A structure of a graft was heterogeneous, areas of osteoporosis alternated with areas of increased density. The quickest resorption was observed in a spongy layer of a bone autograft against a background of hardening and sclerosing of a cortical layer. Thanks to this phenomenon, a cortical-spongy graft looked like a tubular implant in some cases. Such changes were watched in 7.5±3.9 months. Mechanical strength of autografts reduced to a considerable extent during this period; sometimes it resulted in appearance or augmentation of local deformities of the spine (Fig.17).

The third period was characterized by formation of an integral bone block. A structure of autografts became more homogenous and was very close to that of vertebral bodies. Spiral CT demonstrated residual cavities. Formation of a complete bone block in the cervical spine took place in 12.6±1.5 months. As for the thoracic and lumbar spine, it appeared in 24.6±3.8 months. (Fig.18).

Spiral CT made it possible to detect several disorders in the process of autograft remodeling, which led to formation of a bone block with insufficient reliability. Multiple different-size cavities, formed in the structure of cortical-spongy autografts, were present in 7 (14.2%) out of 49 cases. A spongy bone of the upper flaring portion of the ilium looked like a tubular bone in 4 patients (8.2%). Resorption resulted in formation of a fibrous block in 2 cases (4.1%).

A reliable bone block was watched in the majority of cases (35 men, 71.1%). We found out, that the quickest remodeling was typical of a cortical-spongy autograft; in its turn it promoted quicker formation of a bone block. At the same time a process of remodeling of autografts, taken from ribs, was longer; first of all resorption took place in a spongy layer; external cortical layers of ribs became more dense; it was followed by formation of a reliable bone block without complete bone regeneration. Processes of remodeling of bone transplants were faster in the cervical spine due to more intensive blood circulation. At the same time formation of residual cavities and heterogeneity of a bone block were watched mainly in the cervical spine as well.

A process of formation of a bone block in groups 2 (n=37) and 3 (n=35) was analogous to that, watched in group 1.

The first period was characterized by smooth outlines of a graft. There was a lucid streak of 1 mm in a zone of a graft-bone tissue contact. This area of resorption was to some extent a borderline, where a process of formation of new bone tissue took place. X-rays, taken during this period, showed, that a graft surface was uneven and corroded in areas of its close contact with walls of a bone bed. These findings were watched in 3.6±2.4 months after implantation (the beginning of a bone block formation).

Measurements of mineral density of grafts and adjacent tissue of a bone bed were carried out. They showed marked reduction of mineral density of graft edges, adjacent to walls of a bone bed in comparison with a graft center. This difference was equal to 290±3 HU in a month after implantation and reached 931±1 HU by the 4th month. Besides, there was a simultaneous process of consolidation of bone tissue, being in a direct contact with a graft. Comparison of mineral density of bone tissue of a vertebral body, adjacent to a graft and in a remote area, demonstrated that the first value was bigger by 80±2 HU. Initial mineral density in the middle of porous M-31 and M-12 grafts was 2285±3 HU; it reduced up to 2163±2 HU 4 months later (Fig.19).

The second period was characterized by resorption of graft edges. They became more indistinct with turning into newly-formed osseous trabeculae; a bone density in a zone of its contact with graft edges increased. Mineral density near a graft edge was 127±3 HU. X-ray and spiral CT examinations showed, that a streak between a graft and bone bed was absent in many areas; transition from margins of a bone bed to a graft was smooth. According to data of spiral CT-densitometry, the difference in mineral density of central and marginal parts of a graft was 982±2 HU; it was equal to 2055±1 HU in its center. Thus, density in a graft center became smaller only by 208±2 HU in 6 months after operation. These structural changes in a graft and bone bed were watched by us in 7.8±3.4 months after implantation (Fig.20).

The third period (8-16 months) consisted in further formation of a bone-biositall block. Edges of a graft merged with a bone bed. It happened because a graft was covered with newly-formed bone tissue. Fragmentation of implants in the cervical spine and their substitution by newly-formed bone tissue took place during this period in 3 cases (13.6%). Formation of a fibrous capsule between a graft and a bone bed was watched it 3 patients (13.6%) as well. Spiral CT-densitometry revealed a tendency to reduction of difference in mineral density between a center and edges of a graft (2215±1 HU and 883±2 HU respectively). A complete bone block appeared in 11.6±1.1 months (Fig.21).

Combined plasty of defects of vertebral bodies at the level of the thoracic and lumbar spine was performed with application of autografts, taken from ribs; a fragment of the upper flaring portion of the ilium was transplanted in 2 cases. A biositall graft accounted for not less than 60.0% of a volume of plastic material. Glass-ceramic materials, as well as other grafts, possessing osteoprotective and osteoconductive properties, do not contain organic substances and can be implanted to any patient. However, organic substances, present in autografts, have osteoinductive properties, which accelerate a process of formation of a bone block.

Formation of a bone-biositall block was a much quicker process in all cases as compared to applied free autografts and biositall. A complete bone block developed in 7.8±1.3 months.

Periods of formation of a bone-biositall block were a bit shorter, than in application of autografts and biositall. Changes, watched on X-ray and spiral CT examinations, were analogous, but they took place during a shorter period of time. The optimum version of substituting defects of vertebral bodies at the level of the thoracic and lumbar spine is combined plasty by porous biositalls and autografts. This plasty is characterized by optimum reliability, good osteoconductive and osteoinductive properties, promoting quick formation of a strong bone-biositall block without loss of correction of the vertebral column, achieved during operation.

Conclusions

REFERENCES

  1. Vagner E.I., Denisov A.S., Skryabin V.L. Carbon material of a new generation in endoprosthetics of bones and joints. - Perm, 1993. - 64 P. (Rus.).
  2. Williams D.F., Rouf R. Implants in surgery. - Moscow, 1978. - 552 P. (Rus.).
  3. Vinogradova T.R., Lavrishcheva G.I. Regeneration and bone transplantation. - Moscow, 1974. - P. 175 (Rus.).
  4. Voronovich I.R., Petrenko A.M., Dulub O.I. Methods of anterior spondylodesis of the lumbosacral spine // Orthopedics, Traumatology and Prosthetics. - 1987. - N 6. - P. 56 (Rus.).
  5. Gruntovsky G.Kh., Klepach N.S. Principles of the spine stabilization. Errors and complications // Osteosynthesis, errors and complications: Proc. of the I Republican Research and Practice Conf. of Traumatologists-Orthopedists of the Crimea. - Sudak, 1992. - P. 44-46 (Rus.).
  6. Elizarov V.G., Zverev E.V., Buslov I.V. Clinical-tactical classification of compression-flexion injuries of the thoracic and lumbar spine // Orthopedics, Traumatology and Prosthetics. - 1990. - N 11. - P. 24-28 (Rus.).
  7. Korzh A.A., Prodan A.I. Technical peculiarities of shortening of the spine and reconstruction of the spinal cord in patients with complicated injuries of the thoracic and lumbar vertebrae // Transactions of the Crimean Medical Institute. -1989. - V. 116. -P. 91-94 (Rus.).
  8. Korzh A.A., Degtyarev E.V., Gruntovsky G.Kh. Corundum ceramics, prospects of its application in restorative surgery of bones and joints // Orthoped. Traumatology. - 1981. - N 1. - P. 5-8 (Rus.).
  9. Lysenok L.N. Cellular aspects of substitution of bone tissue defects with glass- ceramic grafts. // Klinicheskaya transplantologiya i stomatologiya. - 2001. - N 3-4 (17-18). - P. 109-111 (Rus.).
  10. Pelmutter O.A. Spinal trauma. - Nizhny Novgorod. - 2000. - 144 P. (Rus.).
  11. Prodan A.I., Rakhimov U.R. Prognostication of results and choice of the optimum method of treatment of uncomplicated fractures of the thoracic and lumbar vertebrae//Orthopedics, Traumatology and Prosthetics. - 1990. - N 6. - P. 47-51 (Rus.).
  12. Tsivyan Ya.L. Injuries of the spine. - Moscow: Medicine, 1971. - 312 P. (Rus.).
  13. Yumashev G.S., Kurbanov N.M. Reconstructive operations in injuries of the spine and spinal cord. - Tashkent: Ibn-Sina Publishing House, 1991. - 188 P. (Rus.).
  14. Brantigan J.W., McAfee P.C., Cunningham B.W. et. al. Interbody lumbar fusion using a carbon fiber cage implant versus allograft bone // Spine. - 1994. - Vol. 19, N 13. - P. 1436-1444.
  15. Frankel H.L., Hancock D.O., Hyslop G., Melzak J., Mochaelis Z.S., Ungar G.H., Vernon J.D., Walsh J.J. The value of postural reduction in the initial management of closed injuries of the spine with paraplegia and tetraplegia // Paraplegia. - 1969. - N 7. - P. 179-192.
  16. Cobb J.R. Outline for the study of scoliosis // In The Am. Academy of Orthop, surgeons: instructional Course Lecture. - 1948. -No 5. - P.276.
  17. otler J.M., Cotler H.B. Spinal fusion: science and technique.- New York; Berlin; London; Springer-Verlag, 1990. - 407 p.
  18. Muschler G.F., Negami S., Hyodo A. et. al. Evaluation of collagen ceramic composite graft materials in a spinal fusion model see comments // Clin. Orthop. - 1996. - Vol. 328, N 7. - P. 250-260.