- Email: [email protected]
Fractures of thoracolumbar spine: monosegmental fixation
Injury, Int. J. Care Injured (2005) 36, S-B90—S-B97
www.elsevier.com/locate/injury
Basic concepts relevant to the design and Fractures of thoracolumbar spine: development of fixation the Point Contact Fixator (PC-Fix) monosegmental StephanLA M.Defino, PerrenPiero and Scarparo Helton Joy S. Buchanan Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Faculty of Medicine AO/ASIF Research 7270 Preto, Davos,SP, Switzerland of Ribeirão Preto, Institute, UniversityClavadelerstrasse, of São Paulo, Ribeirão Brazil AO/ASIF Research Institute, Clavadelerstrasse, 7270 Davos, Switzerland
KEYWORDS: Thoracolumbar KEYWORDS: One silly fountain; fractures; spinal Progressivepedical dwarves; fractures; Umpteen monomats; fixation; Five silly trailers; segmental fixation; spinal fixation; spinal trauma.
Summary1 We studied 18 patients with fractures of the thoracolumbar spine 1 the undergoing surgical of marries posterior fixation and Summary bla bla bla blatreatment One aardvark themonosegmental pawnbroker, even though five arthrodesis. Patient follow-up from 2–12 (mean: 6.65 ± 2.96), and bourgeois cats tickled umpteenranged Macintoshes, but years two obese elephants drunkenly the patients were assessed by clinical study, Paul, and functowed umpteen almost irascible sheep. evaluation, Two bureauxradiographic easily telephoned even tional Thegossips, parameters usedelephant for clinical evaluation werewart the Denis thoughevaluation. the wart hogs but one tastes partly putrid hogs, pain scale and neurological evaluation the Frankel while a bought subjective because umpteen purple botulisms kissesbyMark, althoughscale, the subways one evaluation of the final result was made the patients themselves. Kyphosis of extremely angst-ridden lampstand, evenbythough five obese televisions perused the injured vertebral segment,mats the auctioned height of the diskbureau, of this although segment,two andtrailthe subways, then five progressive off the presence of bone reabsorption around the implant five werespeedy the parameters for ers grew up, but irascible Jabberwockies untangles fountains,used yet one radiographic Functional evaluation wastwo performed the Denis work cat ran away,evaluation. then the trailer very cleverly kisses irascibleby: bureaux. scale; the Oswestry disability index; and the SF-36 questionnaire. Clinical evaluation revealed low residual pain rates and a high level of patient satisfaction with the final result. Functional evaluation showed that 95.5% of the patients returned to work on a full-time basis, presented with a low disability index (Oswestry = 10.33) and followed the profile of the North American population when assessed by the SF-36 questionnaire. Radiographic evaluation revealed increased kyphosis in the fixed vertebral segment during the late postoperative period, accompanied by a reduced height of the intervertebral disk. There was no implant break, and no signs of pseudoarthrosis were observed in any patient. The clinical, functional, and radiographic results observed show that posterior monosegmental fixation is an adequate and satisfactory procedure to be used in specific types of thoracolumbar spine fractures.
Introduction The surgical treatment of thoracolumbar spine fractures has undergone profound changes in recent decades, with emphasis on the preservation of intact segments (short arthrodesis) and on the decreased need for immobilization during the postoperative period [1–3]. Biomechanical studies have demonstrated that in the upright position, 80–90% of the axial com1
Abstracts in German, French, Italian, Spanish, Japanese, and Russian are printed at the end of this supplement.
pression forces are absorbed by the anterior part of the spine (body and intervertebral disk), while the posterior articular facets absorb the remaining 10–20%. The erector muscles of the trunk act as a tension band and their action stabilizes the passive distribution of the pressures on the anterior and posterior portions of the spine [4] (Fig 1). In certain types of fractures of the thoracolumbar spine, the application of biomechanical knowledge of the vertebral segment together with the use of pedicular implants has permitted the execution of monosegmental arthrodesis without the need for external immobilization during the postoperative period; a
0020–1383/$ — see front matter # 2005 Published by Elsevier Ltd. doi:10.1016/j.injury.2005.06.019
Fractures of thoracolumbar spine: monosegmental fixation
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Patients and methods
Fig 1: Load distribution at the vertebral segment.
fact that represents maximum preservation of intact vertebral segments. The objective of the present study was to report the results of posterior monosegmental fixation and arthrodesis in treating specific types of fractures of the thoracolumbar posterior spine.
Fig 2: Case 4.
The current study was conducted on 18 patients with fractures of the thoracolumbar spine treated by posterior monosegmental fixation and arthrodesis (Fig 2 and 3). 17 patients were males and one was a female, ranging in age from 22–55 years (mean: 35.36 + 8.26). The causes of the fractures were motor vehicle accidents in 17 patients (94.4%) and fall from a height in one (5.5%). The lesion was localized in T10–T11 in two patients (11.1%), T11–T12 in four patients (22.2%), T12–L1 in six patients (33.3%), L1–L2 in two patients (11.1%), L2–L3 in one patient (5.5%), and in L3–L4 in three patients (16,6%). According to the 1994 classification of Magerl et al [5], eleven fractures were Type B1 (61.1%), three were Type B2 (16.6%), one was Type B3 (5.5%), and three were Type C (16.6%). Evaluation of neurological status according to the classification of Frankel et al [6] showed
Fig 3: Case 14.
(a) and (b): Preoperative x-rays. (a) and (b): Preoperative x-rays. (c): Preoperative CT showing the increased distance between espinous processes.
(c) and (d): Intraoperative views showing the posterior ligamentar lesion and internal fixation.
(e) and (f): The 4-year postoperative x-rays.
(d) and (e): Intraoperative views showing the ligamentar lesion and the internal fixation.
(f) and (g): The 2year postoperative x-rays.
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that eleven patients belonged to Group E (61.1%), two to Group D (11.1%), one to Group B (5.5%), and four to Group A (22.2%). Combined injuries such as long bone fracture and abdominal trauma were present in six patients (33.3%). Indication for surgical intervention was directly related to the presence of instability of the injured vertebral segment and to neurological deficit. Posterior monosegmental fixation was performed in Type B and C fractures according to the classification of Magerl et al [5], with an intact vertebral body for load support. All patients were treated by monosegmental posterior fixation and arthrodesis of the injured vertebral segment using an autogenous corticocancellous bone graft removed from the posterior iliac bone. The vertebral segment was stabilized by bilateral pedicular fixation using the USIS (Ulrich) system of vertebral fixation in nine patients (50%), 6.0 mm USS pedicular screws (Synthes) in six (33.3%), and the Internal Fixator (Synthes) in three (16.6%) (Table 1). During the postoperative period, patients did not use external immobilization and there was no limitation on walking or rehabilitation, which was performed according to the general condition of the patients and their pain response.
Patient Lesion Level
Type of lesion
Neurological Implant Deficit (Frankel)
Followup (years)
1
T11-T12
B2
D
USS T11-12
2
2
T12-L1
B1
E
USIS T12-L1
9
3
L3-L4
B2
E
USS L3-4
5
4
L1-L2
B1
E
IF L1-L2
4
5
L2-L3
B2
E
USIS L2-3
6
T11-T12
B1
E
USIS T11-T12
10
8
7
T12-L1
B1
E
USIS T12-L1
12
8
T10-T11
C1
A
USIS T10-11
8
9
T12-L1
B1
A
USIS T12-L1
7
10
T12-L1
B1
A
USIS T12-L1
9
11
T11-T12
B1
A
USS T11-12
6
12
L1-L2
C2
E
IF L1-L2
4
13
L3-L4
C2
E
USS L3-4
3
14
T12-L1
B1
E
IF T12-L1
2
15
T11-T12
B1
E
USIS T12-11
8
16
T10-T11
B3
B
USS T10-11
5
17
T12-L1
B1
D
USS T12-L1
18
L2-L3
B2
E
USIS L2-3
5 10
Table 1: Level of the lesion, neurological status at the pre op.; type of fracture according Magerl`s classification; level of fixation, type of implant and patients follow-up.
The patients were evaluated on the basis of clinical, radiographic, and functional parameters. Clinical evaluation was performed by subjective evaluation of the final results by the patients themselves (good, fair, poor) and by the Denis pain scale [7] (Table 2). Functional evaluation was performed using the work scale of Denis [7] (Table 3), the Oswestry Disability questionnaire [8, 9], and the Short-Form-36 General Health Survey questionnaire [10, 11]. The radiographic parameters used were measurement of initial kyphosis of the injured vertebral segment and the kyphosis of the same segment during the immediate and late postoperative periods. The loss of height of the intervertebral disk of the fixed vertebral segment (late postoperative period compared to the immediate postoperative period) and the bone changes around the implants were also evaluated. The data regarding the measurements of the kyphotic angle of the injured vertebral segment during the preoperative, immediate postoperative and late postoperative periods were analyzed statistically by the Student t test after verification of sample normality by the Kolmogorov-Smirnov test.
Pain
P1: P2: P3:
P4: P5:
no pain occasional minimal pain; no need for medication moderate pain, occasionally medications e no interruption of work or activities of daily living moderate to severe pain, occasionally absent from work; significant changes in activities of daily living Constant, severe pain; chronic pain medications
Table 2: Denis Pain Scale.
return to previous employment (heavy labor) or physically demanding activities able to return to previous employment W2: (sedentary) or return to heavy labor with restrictions unable to return to previous employment W3: but works full time at new job W4: unable to return to full time work
Work W1:
W5: no work, completely disabled Table 3: Denis Work Scale.
Fractures of thoracolumbar spine: monosegmental fixation
Results Patient follow-up ranged from 2–12 years (mean: 6.65 ± 2.93). Upon clinical evaluation, one patient progressed from Frankel D to E [6], while the remaining ones did not show any neurological changes. In the subjective evaluation performed by the patients, the final result was considered to be good by 14 of them (77.7%), fair by three (16.6%), and poor by one (5.5%). Pain evaluation according to the Denis scale [7] showed that six patients had no pain (33.3%), nine had occasional pain (50%), one had moderate pain (5.5%), and one had moderate to intense pain (5.5%) (Fig 4). Radiographic evaluation revealed that kyphosis of the fractured vertebral segment ranged from:
%
P A T I E N T S
60 50 40 30 20 10 0
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0°–36° (mean: 14.4° ± 9.62) during the preoperative period; from 10° of lordosis to 20° of kyphosis (mean: 3.72 ± 6.73° of kyphosis) during the immediate postoperative period; and from 10° of lordosis to 20° of kyphosis during the late postoperative period (mean: 7.72 ± 7.73° of kyphosis). At late evaluation, Fig 6: Case 8.
(a) and (b): Preoperative x-rays of Type C fracture presenting a rib dislocation.
(c) and (d): Initial postoperative x-rays.
(e) and (f): The 8-year postoperative x-rays.
P1 no pain
P2
P3
occasional moderate pain pain
P4
P5
severe pain
constant, severe pain
Fig 4: Long term follow-up results according to Denis pain scale.
Fig 7: Case 1. (a), (b) and (c): Preoperative x-ray, CT, and MRI showing the posterior ligamentar lesion.
Fig 5: Case 6. (a) and (b): Preoperative x-rays. (c): Clinical picture after 3 months. (d) and (e): 10-year postoperative x-rays. Observe the reduction in the disc height.
(d) and (e): Postoperative x-rays.
(f) and (g): The 2year postoperative x-rays.
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Fig 8: Case 5.
all patients except one presented with a reduction of at least 50% in the height of the intervertebral disk of the fixed vertebral segment. In four patients (22.2%), reabsorption was observed around the bony material, but with no signs of break. Integration of the bone graft and arthrodesis consolidation was observed in all patients, with no instance of pseudoarthrosis (Table 4, Figs 5, 6, 7, and 8). A statistically significant difference was observed between the initial kyphosis of the injured vertebral segment and the kyphosis observed in the immediate postoperative period (p<0.001). A significant difference was also observed between the kyphosis values of the injured vertebral segment measured during the immediate postoperative period and those measured during the late period (p=0.001) and between those measured during the preoperative period and the late postoperative period (p=0.001). Functional evaluation showed that six patients returned to their previous job involving intense physical activity (33.3%), ten returned to their previous job involving light physical activity (55.5%), one was forced to change his job but continued to work on a full time basis (5.5%), and one was unable to
(a) and (b): Preoperative x-rays.
(c) and (d): Initial postoperative xrays. (e) and (f): The 8-year postoperative x-rays. Observe the reabsorption around the implants and loss of disc height.
Patient
Pre op
Postoperative
Long term follow-up
Disc height reduction
Bone reabsorption
Arthrodesis
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
10 19 3 15 10 22 30 6 36 10 19 12 0 5 25 10 20 8
6 8 5 0 –4 10 8 3 11 3 2 –6 –10 1 20 4 4 2
18 12 2 4 0 16 11 11 15 4 11 –3 –10 3 20 5 8 4
> 50% 50% > 50% > 50% > 50% > 50% > 50% 50% > 50% > 50% > 50% > 50% 50% ZERO 50% 50% 50% 50%
No No Yes No Yes No Yes No No No No No No Yes No No No No
Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
Table 4: Long term radiological evaluation of the patients showing the segmental kyphosis at the pre op, postoperative and long term follow up; the reduction of disc height at the vertebral segment fixated; the bone reabsorption around the screws and the consolidation of the arthrodesis.
Fractures of thoracolumbar spine: monosegmental fixation
return to work (5.5%) (Fig 9). The mean Oswestry disability index [8, 9] obtained was 10.33 ± 10.87 (range: 0–42) (Table 5) The mean scores obtained with the SF-36 general health survey questionnaire [10, 11], for which the best possible score is 100, were: 60.29 + 28.33 for physical function, 61.66 ± 38.34 for functional limitation, 73.88 ± 24.87 for pain, 68.61 ± 13.91 for general health, 70.5 ± 10.69 for vitality, 75 ± 18.68 for social function, 84.21 ± 24.61 for emotional limitation, and 73.77 ± 8.81 for mental health (Fig 10).
Discussion Over the past decades, the treatment of thoracolumbar spine fractures has greatly improved. This is directly related to a better understanding of the biomechanics of the vertebral segment, to a more
Patients 60 50 40 %
30 20 10 0 W1
previous work (heavy)
W2
W3
previous work (light)
W4
W5
new partial work time full time
disabled
Fig 9: Long term results according to Denis work scale.
S F -3 6
100 80 S C O R E
60
MONOSEGMENTAL FIXATION
40
NORTH AMERICA POPULATION
20 0 PF
Abreviations
PL
PH: PL: P: GH:
P
GH
V
physical function physical limitation pain general health
SF
EL
V: SF: EL: MH:
MH
vitality social function emotional limitation mental health
Fig: 10: Long term results of monosegmental fixation compared to General Health Survey SF-36 average score of the North America population.
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detailed and precise classification of the injuries, and to the development of fixation systems that provide greater mechanical stability [2, 4, 5, 12]. Taken together, these factors have fulfilled the current objectives of surgical treatment of thoracolumbar spine fractures, such as the execution of short arthrodesis for the preservation of non-injured spine segments and the avoidance of external immobilization [1–3]. The use of fixation and posterior monosegmental arthrodesis for the treatment of thoracolumbar spine fractures is the result of the practical application of current knowledge in the field of spinal surgery. The biomechanical concepts support the use of monosegmental fixation for restoring the damaged tension band as long as there is integrity of the vertebral body for weight support. The more detailed and precise classification of traumatic injuries permits the recognition and grouping of injuries involving injury to the posterior elements of the vertebral segment without vertebral body fractures. These lesions correspond to Type B and C injuries in the classification of Magerl et al [5] and the use of this classification permits a more precise and detailed grouping of such injuries, with better clarification of the results and more accurate indication of treatment. Transpedicular fixation represents a great advance in the field of spinal surgery, providing satisfactory stability of the vertebral segment by means of short fixation. Monosegmental vertebral fixation is a clear example of this. The literature concerning this topic is full of clinical examples of spine fractures and it can be seen that as the rigidity of the fixation systems decreases, the area of vertebral arthrodesis and instrumentation becomes more extensive. Despite the controversy existing about the treatment of fractures of the thoracolumbar spine, the patients in the present series may be one of the few about which there is not much discussion on indication for surgical treatment. The patients in our series presented with Type B or C fractures in the Magerl classification [5], which involve associated injury to the posterior elements. The concept of the inability
1-“Normal” population
10,19%
2-Pelvic fractures
13,26%
3-Spondilolistesis
26,63%
4-Cronic lumbar pain
43,30%
5-Monosegmental fixation
10,33%
Table 5: Results of Oswestry disability index (Roland M & Fairbank J, 2000) compared to long term results of monosegmental fixation.
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of these injuries to heal without internal fixation, and of the stability of the vertebral segment to be reestablished, has been well defined [13]. These injuries are unstable, and posttraumatic deformity progresses when treated conservatively, as well as increased pain and neurological deficit. The type of implant used for fracture stabilization reflects the rapid development and refinement of vertebral implants. In the earlier patients in our series, pedicular screws associated with threaded rods of smaller caliber were used, whereas in the more recent patients, the fixation systems involved smooth bars of larger caliber. Despite the mechanical superiority of the systems of fixation with rods of larger caliber, the clinical and radiological results were similar in the groups of patients studied. Clinical and functional evaluation of the patients yielded satisfactory results for all parameters analyzed, and compare favorably with the data reported by others [14–17]. A high rate of return to professional activities was observed. However, analysis of the results clearly demonstrate the involvement of biopsychosocial factors, since some patients had no neurological deficit and good radiographic results, while their functional evaluation yielded unsatisfactory scores. The radiographic evaluation of the fractured vertebral segment showed a reduction in the height of the intervertebral disk in all patients except one; this is understandable considering the presence of damage to the intervertebral disk in these lesions. The increased kyphosis of the fractured vertebral segment was significant when compared to the values obtained during the immediate postoperative period and was directly related to the reduction in the height of the injured intervertebral disk. This loss of kyphosis of the injured vertebral segment did not affect the clinical or functional result of the patients, confirming observations reported by others [16, 18, 19] who also obtained good clinical results in patients for whom the degree of physiological kyphosis was not reconstituted. The loss of correction on the sagittal plane did not lead to hardware failure. Arthrodesis was observed in all patients. The reabsorption halo observed around some implants may have been related to stress shielding, since arthrodesis was consolidated in all cases and there was no break or loosening of the implants used. Posterior monosegmental arthrodesis is a procedure that can be used to treat complex injuries of the vertebral segment as long as the vertebral body is not fractured and maintains its supporting ability. This procedure can be used in patients with severe neurological damage or in patients submitted to laparotomy, permitting early rehabilitation because of the lower morbidity of the procedure. With the
H LA Defino, P Scarparo
help of computer-assisted surgery that permits the suprafascial placement of implants, or with the use of bone substitutes, which avoids the need for iliac crest graft, the morbidity of this procedure can be reduced even more.
References 1. Defino LA, Fuentes AE, Remondi PH, et al (1998) Monosegmental fixation of thoracolumbar spine fractures. Braz J Orthop; 33:119–124. 2. Haher TR, Felmly WT, O’Brien M (1997) Thoracic and lumbar fractures: diagnosis and treatment. Bridwell KH, De Wald RL (eds). The textbook of spinal surgery. Philadelphia: JB Lippincot. 3. Muller EJ, Muhr G (1997) Wibelsäulenverletzungen. Stuttgart: Georg Thieme Verlag. 4. Harms J (1992) Screw-threaded rod system in spinal fusion surgery. State of the art review. Spine; 6:541–577. 5. Magerl F, Aebi M, Gertzbein SD, et al (1994) A comprehensive classification of thoracic and lumbar injuries. Eur Spine J; 3(4):184–201. 6. Frankel HL, Hancock DO, Hyslop G, et al (1969) The value of postural reduction in the initial management of closed injuries of the spine with paraplegia and tetraplegia. I. Paraplegia; 7(3):179–192. 7. Gotzen L, Puplat D, Junge A (1992) [Indications, technique and results of monosegmental dorsal spondylodesis in wedge compression fractures (grade II) of the thoracolumbar spine.] Unfallchirurg; 95(9):445–454. 8. Fairbank JC, Pynsent PB (2000) The Oswestry Disability Index. Spine; 25(22):2940–2953. 9. Roland M, Fairbank J (2000) The Roland-Morris Disability Questionnaire and the Oswestry Disability Questionnaire. Spine; 25(24):3115–3124. 10. Grevitt M, Khazim R, Weeb J, et al (1997) The short form-36 health survey questionnaire in spine surgery. J Bone Joint Surg Br; 79(1):48–52. 11. Ware JE Jr (2000) SF-36 health survey update. Spine; 25(24):3130–3139. 12. Stauffer ES (1997) The use of the AO “fixateur interne” for thoracic and lumbar fractures. Bridwell KH, DeWald RL (eds), The textbook of spinal surgery. Philadelphia: JB Lippincott. 13. Louis R (1977) [Unstable fractures of the spine. III. Instability. A. Theories concerning instability.] Rev Chir Orthop Reparatrice Appar Mot; 63(5):423–425. 14. Finkelstein JA, Wai EK, Jackson SS, et al (2003) Single-level fixation of flexion distraction injuries. J Spinal Disord Tech; 16(3):236–242. 15. Gotzen L, Puplat D, Junge A (1992) [Indications, technique and results of monosegmental dorsal spondylodesis in wedge compression fractures (grade II) of the thoracolumbar spine.] Unfallchirurg; 95(9):445–454. 16. Jung A, Gotzen L, Garrel TV, et al (1997) Monosegmentale Fixateur Interne Instrumentation und Fusion in der Behandlung von Frakturen der Thorakolumbalen Wirbelsäule, Unfallchirurg; 100:880–887.
Fractures of thoracolumbar spine: monosegmental fixation
17. Liu YJ, Chang MC, Wang ST, et al (2003) Flexion-distraction injury of the thoracolumbar spine. Injury; 34(12):920–923.
Correspondence address:
18. Defino LA, Fuentes AE, Remondi PH, et al (2000) Non surgical treatment of thoracolumbar spine fractures. Braz J Orthop; 35:301–308.
Dr Helton LA Defino Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus Faculty of Medicine of Ribeirão Preto University of São Paulo 14048-900 Ribeirão Preto, SP, Brazil phone 1: +55 16 633 0336 phone 2: +55 16 602 2513 email: [email protected]
19. Sanderson PL, Fraser RD, Hall DJ, et al (1999) Short segment fixation of thoracolumbar burst fractures without fusion. Eur Spine J; 8(6):495–500.
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www.elsevier.com/locate/injury
Basic concepts relevant to the design and Fractures of thoracolumbar spine: development of fixation the Point Contact Fixator (PC-Fix) monosegmental StephanLA M.Defino, PerrenPiero and Scarparo Helton Joy S. Buchanan Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus, Faculty of Medicine AO/ASIF Research 7270 Preto, Davos,SP, Switzerland of Ribeirão Preto, Institute, UniversityClavadelerstrasse, of São Paulo, Ribeirão Brazil AO/ASIF Research Institute, Clavadelerstrasse, 7270 Davos, Switzerland
KEYWORDS: Thoracolumbar KEYWORDS: One silly fountain; fractures; spinal Progressivepedical dwarves; fractures; Umpteen monomats; fixation; Five silly trailers; segmental fixation; spinal fixation; spinal trauma.
Summary1 We studied 18 patients with fractures of the thoracolumbar spine 1 the undergoing surgical of marries posterior fixation and Summary bla bla bla blatreatment One aardvark themonosegmental pawnbroker, even though five arthrodesis. Patient follow-up from 2–12 (mean: 6.65 ± 2.96), and bourgeois cats tickled umpteenranged Macintoshes, but years two obese elephants drunkenly the patients were assessed by clinical study, Paul, and functowed umpteen almost irascible sheep. evaluation, Two bureauxradiographic easily telephoned even tional Thegossips, parameters usedelephant for clinical evaluation werewart the Denis thoughevaluation. the wart hogs but one tastes partly putrid hogs, pain scale and neurological evaluation the Frankel while a bought subjective because umpteen purple botulisms kissesbyMark, althoughscale, the subways one evaluation of the final result was made the patients themselves. Kyphosis of extremely angst-ridden lampstand, evenbythough five obese televisions perused the injured vertebral segment,mats the auctioned height of the diskbureau, of this although segment,two andtrailthe subways, then five progressive off the presence of bone reabsorption around the implant five werespeedy the parameters for ers grew up, but irascible Jabberwockies untangles fountains,used yet one radiographic Functional evaluation wastwo performed the Denis work cat ran away,evaluation. then the trailer very cleverly kisses irascibleby: bureaux. scale; the Oswestry disability index; and the SF-36 questionnaire. Clinical evaluation revealed low residual pain rates and a high level of patient satisfaction with the final result. Functional evaluation showed that 95.5% of the patients returned to work on a full-time basis, presented with a low disability index (Oswestry = 10.33) and followed the profile of the North American population when assessed by the SF-36 questionnaire. Radiographic evaluation revealed increased kyphosis in the fixed vertebral segment during the late postoperative period, accompanied by a reduced height of the intervertebral disk. There was no implant break, and no signs of pseudoarthrosis were observed in any patient. The clinical, functional, and radiographic results observed show that posterior monosegmental fixation is an adequate and satisfactory procedure to be used in specific types of thoracolumbar spine fractures.
Introduction The surgical treatment of thoracolumbar spine fractures has undergone profound changes in recent decades, with emphasis on the preservation of intact segments (short arthrodesis) and on the decreased need for immobilization during the postoperative period [1–3]. Biomechanical studies have demonstrated that in the upright position, 80–90% of the axial com1
Abstracts in German, French, Italian, Spanish, Japanese, and Russian are printed at the end of this supplement.
pression forces are absorbed by the anterior part of the spine (body and intervertebral disk), while the posterior articular facets absorb the remaining 10–20%. The erector muscles of the trunk act as a tension band and their action stabilizes the passive distribution of the pressures on the anterior and posterior portions of the spine [4] (Fig 1). In certain types of fractures of the thoracolumbar spine, the application of biomechanical knowledge of the vertebral segment together with the use of pedicular implants has permitted the execution of monosegmental arthrodesis without the need for external immobilization during the postoperative period; a
0020–1383/$ — see front matter # 2005 Published by Elsevier Ltd. doi:10.1016/j.injury.2005.06.019
Fractures of thoracolumbar spine: monosegmental fixation
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Patients and methods
Fig 1: Load distribution at the vertebral segment.
fact that represents maximum preservation of intact vertebral segments. The objective of the present study was to report the results of posterior monosegmental fixation and arthrodesis in treating specific types of fractures of the thoracolumbar posterior spine.
Fig 2: Case 4.
The current study was conducted on 18 patients with fractures of the thoracolumbar spine treated by posterior monosegmental fixation and arthrodesis (Fig 2 and 3). 17 patients were males and one was a female, ranging in age from 22–55 years (mean: 35.36 + 8.26). The causes of the fractures were motor vehicle accidents in 17 patients (94.4%) and fall from a height in one (5.5%). The lesion was localized in T10–T11 in two patients (11.1%), T11–T12 in four patients (22.2%), T12–L1 in six patients (33.3%), L1–L2 in two patients (11.1%), L2–L3 in one patient (5.5%), and in L3–L4 in three patients (16,6%). According to the 1994 classification of Magerl et al [5], eleven fractures were Type B1 (61.1%), three were Type B2 (16.6%), one was Type B3 (5.5%), and three were Type C (16.6%). Evaluation of neurological status according to the classification of Frankel et al [6] showed
Fig 3: Case 14.
(a) and (b): Preoperative x-rays. (a) and (b): Preoperative x-rays. (c): Preoperative CT showing the increased distance between espinous processes.
(c) and (d): Intraoperative views showing the posterior ligamentar lesion and internal fixation.
(e) and (f): The 4-year postoperative x-rays.
(d) and (e): Intraoperative views showing the ligamentar lesion and the internal fixation.
(f) and (g): The 2year postoperative x-rays.
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H LA Defino, P Scarparo
that eleven patients belonged to Group E (61.1%), two to Group D (11.1%), one to Group B (5.5%), and four to Group A (22.2%). Combined injuries such as long bone fracture and abdominal trauma were present in six patients (33.3%). Indication for surgical intervention was directly related to the presence of instability of the injured vertebral segment and to neurological deficit. Posterior monosegmental fixation was performed in Type B and C fractures according to the classification of Magerl et al [5], with an intact vertebral body for load support. All patients were treated by monosegmental posterior fixation and arthrodesis of the injured vertebral segment using an autogenous corticocancellous bone graft removed from the posterior iliac bone. The vertebral segment was stabilized by bilateral pedicular fixation using the USIS (Ulrich) system of vertebral fixation in nine patients (50%), 6.0 mm USS pedicular screws (Synthes) in six (33.3%), and the Internal Fixator (Synthes) in three (16.6%) (Table 1). During the postoperative period, patients did not use external immobilization and there was no limitation on walking or rehabilitation, which was performed according to the general condition of the patients and their pain response.
Patient Lesion Level
Type of lesion
Neurological Implant Deficit (Frankel)
Followup (years)
1
T11-T12
B2
D
USS T11-12
2
2
T12-L1
B1
E
USIS T12-L1
9
3
L3-L4
B2
E
USS L3-4
5
4
L1-L2
B1
E
IF L1-L2
4
5
L2-L3
B2
E
USIS L2-3
6
T11-T12
B1
E
USIS T11-T12
10
8
7
T12-L1
B1
E
USIS T12-L1
12
8
T10-T11
C1
A
USIS T10-11
8
9
T12-L1
B1
A
USIS T12-L1
7
10
T12-L1
B1
A
USIS T12-L1
9
11
T11-T12
B1
A
USS T11-12
6
12
L1-L2
C2
E
IF L1-L2
4
13
L3-L4
C2
E
USS L3-4
3
14
T12-L1
B1
E
IF T12-L1
2
15
T11-T12
B1
E
USIS T12-11
8
16
T10-T11
B3
B
USS T10-11
5
17
T12-L1
B1
D
USS T12-L1
18
L2-L3
B2
E
USIS L2-3
5 10
Table 1: Level of the lesion, neurological status at the pre op.; type of fracture according Magerl`s classification; level of fixation, type of implant and patients follow-up.
The patients were evaluated on the basis of clinical, radiographic, and functional parameters. Clinical evaluation was performed by subjective evaluation of the final results by the patients themselves (good, fair, poor) and by the Denis pain scale [7] (Table 2). Functional evaluation was performed using the work scale of Denis [7] (Table 3), the Oswestry Disability questionnaire [8, 9], and the Short-Form-36 General Health Survey questionnaire [10, 11]. The radiographic parameters used were measurement of initial kyphosis of the injured vertebral segment and the kyphosis of the same segment during the immediate and late postoperative periods. The loss of height of the intervertebral disk of the fixed vertebral segment (late postoperative period compared to the immediate postoperative period) and the bone changes around the implants were also evaluated. The data regarding the measurements of the kyphotic angle of the injured vertebral segment during the preoperative, immediate postoperative and late postoperative periods were analyzed statistically by the Student t test after verification of sample normality by the Kolmogorov-Smirnov test.
Pain
P1: P2: P3:
P4: P5:
no pain occasional minimal pain; no need for medication moderate pain, occasionally medications e no interruption of work or activities of daily living moderate to severe pain, occasionally absent from work; significant changes in activities of daily living Constant, severe pain; chronic pain medications
Table 2: Denis Pain Scale.
return to previous employment (heavy labor) or physically demanding activities able to return to previous employment W2: (sedentary) or return to heavy labor with restrictions unable to return to previous employment W3: but works full time at new job W4: unable to return to full time work
Work W1:
W5: no work, completely disabled Table 3: Denis Work Scale.
Fractures of thoracolumbar spine: monosegmental fixation
Results Patient follow-up ranged from 2–12 years (mean: 6.65 ± 2.93). Upon clinical evaluation, one patient progressed from Frankel D to E [6], while the remaining ones did not show any neurological changes. In the subjective evaluation performed by the patients, the final result was considered to be good by 14 of them (77.7%), fair by three (16.6%), and poor by one (5.5%). Pain evaluation according to the Denis scale [7] showed that six patients had no pain (33.3%), nine had occasional pain (50%), one had moderate pain (5.5%), and one had moderate to intense pain (5.5%) (Fig 4). Radiographic evaluation revealed that kyphosis of the fractured vertebral segment ranged from:
%
P A T I E N T S
60 50 40 30 20 10 0
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0°–36° (mean: 14.4° ± 9.62) during the preoperative period; from 10° of lordosis to 20° of kyphosis (mean: 3.72 ± 6.73° of kyphosis) during the immediate postoperative period; and from 10° of lordosis to 20° of kyphosis during the late postoperative period (mean: 7.72 ± 7.73° of kyphosis). At late evaluation, Fig 6: Case 8.
(a) and (b): Preoperative x-rays of Type C fracture presenting a rib dislocation.
(c) and (d): Initial postoperative x-rays.
(e) and (f): The 8-year postoperative x-rays.
P1 no pain
P2
P3
occasional moderate pain pain
P4
P5
severe pain
constant, severe pain
Fig 4: Long term follow-up results according to Denis pain scale.
Fig 7: Case 1. (a), (b) and (c): Preoperative x-ray, CT, and MRI showing the posterior ligamentar lesion.
Fig 5: Case 6. (a) and (b): Preoperative x-rays. (c): Clinical picture after 3 months. (d) and (e): 10-year postoperative x-rays. Observe the reduction in the disc height.
(d) and (e): Postoperative x-rays.
(f) and (g): The 2year postoperative x-rays.
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H LA Defino, P Scarparo
Fig 8: Case 5.
all patients except one presented with a reduction of at least 50% in the height of the intervertebral disk of the fixed vertebral segment. In four patients (22.2%), reabsorption was observed around the bony material, but with no signs of break. Integration of the bone graft and arthrodesis consolidation was observed in all patients, with no instance of pseudoarthrosis (Table 4, Figs 5, 6, 7, and 8). A statistically significant difference was observed between the initial kyphosis of the injured vertebral segment and the kyphosis observed in the immediate postoperative period (p<0.001). A significant difference was also observed between the kyphosis values of the injured vertebral segment measured during the immediate postoperative period and those measured during the late period (p=0.001) and between those measured during the preoperative period and the late postoperative period (p=0.001). Functional evaluation showed that six patients returned to their previous job involving intense physical activity (33.3%), ten returned to their previous job involving light physical activity (55.5%), one was forced to change his job but continued to work on a full time basis (5.5%), and one was unable to
(a) and (b): Preoperative x-rays.
(c) and (d): Initial postoperative xrays. (e) and (f): The 8-year postoperative x-rays. Observe the reabsorption around the implants and loss of disc height.
Patient
Pre op
Postoperative
Long term follow-up
Disc height reduction
Bone reabsorption
Arthrodesis
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
10 19 3 15 10 22 30 6 36 10 19 12 0 5 25 10 20 8
6 8 5 0 –4 10 8 3 11 3 2 –6 –10 1 20 4 4 2
18 12 2 4 0 16 11 11 15 4 11 –3 –10 3 20 5 8 4
> 50% 50% > 50% > 50% > 50% > 50% > 50% 50% > 50% > 50% > 50% > 50% 50% ZERO 50% 50% 50% 50%
No No Yes No Yes No Yes No No No No No No Yes No No No No
Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes
Table 4: Long term radiological evaluation of the patients showing the segmental kyphosis at the pre op, postoperative and long term follow up; the reduction of disc height at the vertebral segment fixated; the bone reabsorption around the screws and the consolidation of the arthrodesis.
Fractures of thoracolumbar spine: monosegmental fixation
return to work (5.5%) (Fig 9). The mean Oswestry disability index [8, 9] obtained was 10.33 ± 10.87 (range: 0–42) (Table 5) The mean scores obtained with the SF-36 general health survey questionnaire [10, 11], for which the best possible score is 100, were: 60.29 + 28.33 for physical function, 61.66 ± 38.34 for functional limitation, 73.88 ± 24.87 for pain, 68.61 ± 13.91 for general health, 70.5 ± 10.69 for vitality, 75 ± 18.68 for social function, 84.21 ± 24.61 for emotional limitation, and 73.77 ± 8.81 for mental health (Fig 10).
Discussion Over the past decades, the treatment of thoracolumbar spine fractures has greatly improved. This is directly related to a better understanding of the biomechanics of the vertebral segment, to a more
Patients 60 50 40 %
30 20 10 0 W1
previous work (heavy)
W2
W3
previous work (light)
W4
W5
new partial work time full time
disabled
Fig 9: Long term results according to Denis work scale.
S F -3 6
100 80 S C O R E
60
MONOSEGMENTAL FIXATION
40
NORTH AMERICA POPULATION
20 0 PF
Abreviations
PL
PH: PL: P: GH:
P
GH
V
physical function physical limitation pain general health
SF
EL
V: SF: EL: MH:
MH
vitality social function emotional limitation mental health
Fig: 10: Long term results of monosegmental fixation compared to General Health Survey SF-36 average score of the North America population.
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detailed and precise classification of the injuries, and to the development of fixation systems that provide greater mechanical stability [2, 4, 5, 12]. Taken together, these factors have fulfilled the current objectives of surgical treatment of thoracolumbar spine fractures, such as the execution of short arthrodesis for the preservation of non-injured spine segments and the avoidance of external immobilization [1–3]. The use of fixation and posterior monosegmental arthrodesis for the treatment of thoracolumbar spine fractures is the result of the practical application of current knowledge in the field of spinal surgery. The biomechanical concepts support the use of monosegmental fixation for restoring the damaged tension band as long as there is integrity of the vertebral body for weight support. The more detailed and precise classification of traumatic injuries permits the recognition and grouping of injuries involving injury to the posterior elements of the vertebral segment without vertebral body fractures. These lesions correspond to Type B and C injuries in the classification of Magerl et al [5] and the use of this classification permits a more precise and detailed grouping of such injuries, with better clarification of the results and more accurate indication of treatment. Transpedicular fixation represents a great advance in the field of spinal surgery, providing satisfactory stability of the vertebral segment by means of short fixation. Monosegmental vertebral fixation is a clear example of this. The literature concerning this topic is full of clinical examples of spine fractures and it can be seen that as the rigidity of the fixation systems decreases, the area of vertebral arthrodesis and instrumentation becomes more extensive. Despite the controversy existing about the treatment of fractures of the thoracolumbar spine, the patients in the present series may be one of the few about which there is not much discussion on indication for surgical treatment. The patients in our series presented with Type B or C fractures in the Magerl classification [5], which involve associated injury to the posterior elements. The concept of the inability
1-“Normal” population
10,19%
2-Pelvic fractures
13,26%
3-Spondilolistesis
26,63%
4-Cronic lumbar pain
43,30%
5-Monosegmental fixation
10,33%
Table 5: Results of Oswestry disability index (Roland M & Fairbank J, 2000) compared to long term results of monosegmental fixation.
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of these injuries to heal without internal fixation, and of the stability of the vertebral segment to be reestablished, has been well defined [13]. These injuries are unstable, and posttraumatic deformity progresses when treated conservatively, as well as increased pain and neurological deficit. The type of implant used for fracture stabilization reflects the rapid development and refinement of vertebral implants. In the earlier patients in our series, pedicular screws associated with threaded rods of smaller caliber were used, whereas in the more recent patients, the fixation systems involved smooth bars of larger caliber. Despite the mechanical superiority of the systems of fixation with rods of larger caliber, the clinical and radiological results were similar in the groups of patients studied. Clinical and functional evaluation of the patients yielded satisfactory results for all parameters analyzed, and compare favorably with the data reported by others [14–17]. A high rate of return to professional activities was observed. However, analysis of the results clearly demonstrate the involvement of biopsychosocial factors, since some patients had no neurological deficit and good radiographic results, while their functional evaluation yielded unsatisfactory scores. The radiographic evaluation of the fractured vertebral segment showed a reduction in the height of the intervertebral disk in all patients except one; this is understandable considering the presence of damage to the intervertebral disk in these lesions. The increased kyphosis of the fractured vertebral segment was significant when compared to the values obtained during the immediate postoperative period and was directly related to the reduction in the height of the injured intervertebral disk. This loss of kyphosis of the injured vertebral segment did not affect the clinical or functional result of the patients, confirming observations reported by others [16, 18, 19] who also obtained good clinical results in patients for whom the degree of physiological kyphosis was not reconstituted. The loss of correction on the sagittal plane did not lead to hardware failure. Arthrodesis was observed in all patients. The reabsorption halo observed around some implants may have been related to stress shielding, since arthrodesis was consolidated in all cases and there was no break or loosening of the implants used. Posterior monosegmental arthrodesis is a procedure that can be used to treat complex injuries of the vertebral segment as long as the vertebral body is not fractured and maintains its supporting ability. This procedure can be used in patients with severe neurological damage or in patients submitted to laparotomy, permitting early rehabilitation because of the lower morbidity of the procedure. With the
H LA Defino, P Scarparo
help of computer-assisted surgery that permits the suprafascial placement of implants, or with the use of bone substitutes, which avoids the need for iliac crest graft, the morbidity of this procedure can be reduced even more.
References 1. Defino LA, Fuentes AE, Remondi PH, et al (1998) Monosegmental fixation of thoracolumbar spine fractures. Braz J Orthop; 33:119–124. 2. Haher TR, Felmly WT, O’Brien M (1997) Thoracic and lumbar fractures: diagnosis and treatment. Bridwell KH, De Wald RL (eds). The textbook of spinal surgery. Philadelphia: JB Lippincot. 3. Muller EJ, Muhr G (1997) Wibelsäulenverletzungen. Stuttgart: Georg Thieme Verlag. 4. Harms J (1992) Screw-threaded rod system in spinal fusion surgery. State of the art review. Spine; 6:541–577. 5. Magerl F, Aebi M, Gertzbein SD, et al (1994) A comprehensive classification of thoracic and lumbar injuries. Eur Spine J; 3(4):184–201. 6. Frankel HL, Hancock DO, Hyslop G, et al (1969) The value of postural reduction in the initial management of closed injuries of the spine with paraplegia and tetraplegia. I. Paraplegia; 7(3):179–192. 7. Gotzen L, Puplat D, Junge A (1992) [Indications, technique and results of monosegmental dorsal spondylodesis in wedge compression fractures (grade II) of the thoracolumbar spine.] Unfallchirurg; 95(9):445–454. 8. Fairbank JC, Pynsent PB (2000) The Oswestry Disability Index. Spine; 25(22):2940–2953. 9. Roland M, Fairbank J (2000) The Roland-Morris Disability Questionnaire and the Oswestry Disability Questionnaire. Spine; 25(24):3115–3124. 10. Grevitt M, Khazim R, Weeb J, et al (1997) The short form-36 health survey questionnaire in spine surgery. J Bone Joint Surg Br; 79(1):48–52. 11. Ware JE Jr (2000) SF-36 health survey update. Spine; 25(24):3130–3139. 12. Stauffer ES (1997) The use of the AO “fixateur interne” for thoracic and lumbar fractures. Bridwell KH, DeWald RL (eds), The textbook of spinal surgery. Philadelphia: JB Lippincott. 13. Louis R (1977) [Unstable fractures of the spine. III. Instability. A. Theories concerning instability.] Rev Chir Orthop Reparatrice Appar Mot; 63(5):423–425. 14. Finkelstein JA, Wai EK, Jackson SS, et al (2003) Single-level fixation of flexion distraction injuries. J Spinal Disord Tech; 16(3):236–242. 15. Gotzen L, Puplat D, Junge A (1992) [Indications, technique and results of monosegmental dorsal spondylodesis in wedge compression fractures (grade II) of the thoracolumbar spine.] Unfallchirurg; 95(9):445–454. 16. Jung A, Gotzen L, Garrel TV, et al (1997) Monosegmentale Fixateur Interne Instrumentation und Fusion in der Behandlung von Frakturen der Thorakolumbalen Wirbelsäule, Unfallchirurg; 100:880–887.
Fractures of thoracolumbar spine: monosegmental fixation
17. Liu YJ, Chang MC, Wang ST, et al (2003) Flexion-distraction injury of the thoracolumbar spine. Injury; 34(12):920–923.
Correspondence address:
18. Defino LA, Fuentes AE, Remondi PH, et al (2000) Non surgical treatment of thoracolumbar spine fractures. Braz J Orthop; 35:301–308.
Dr Helton LA Defino Department of Biomechanics, Medicine and Rehabilitation of the Locomotor Apparatus Faculty of Medicine of Ribeirão Preto University of São Paulo 14048-900 Ribeirão Preto, SP, Brazil phone 1: +55 16 633 0336 phone 2: +55 16 602 2513 email: [email protected]
19. Sanderson PL, Fraser RD, Hall DJ, et al (1999) Short segment fixation of thoracolumbar burst fractures without fusion. Eur Spine J; 8(6):495–500.
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