SPINE Volume 39, Number 40, pp E120-E126 ©2015, Lippincott Williams & Wilkins
SURGERY
Comparative Study of 2 Surgical Procedures for Osteoporotic Delayed Vertebral Collapse Anterior and Posterior Combined Surgery Versus Posterior Spinal Fusion With Vertebroplasty Hiroaki Nakashima, MD,* Shiro Imagama, MD, PhD,* Yasutsugu Yukawa, MD, PhD,† Tokumi Kanemura, MD, PhD,‡ Mitsuhiro Kamiya, MD, PhD,§ Masao Deguchi, MD, PhD,¶ Norimitsu Wakao, MD, PhD,§ Takashi Sato, MD,§ Kei Matsuzaki, MD,¶ Go Yoshida, MD, Yukihiro Matsuyama, MD, PhD,** Naoki Ishiguro, MD, PhD,* and Fumihiko Kato, MD†
Study Design. Retrospective comparative study. Objective. To compare the surgical results of anterior and posterior combined surgery (AP) and posterior fixation with vertebroplasty (VP) for treating osteoporotic delayed vertebral collapse. Summary of Background Data. The optimal treatment of osteoporotic delayed vertebral collapse has been controversial. Because of aged patients’ numerous comorbid medical complications and frequent instrumentation failure secondary to osteoporosis, it is challenging for surgeons to manage osteoporotic delayed vertebral collapse. In spite of this, there have been few reports comparing the surgical results. Methods. A total of 93 patients with osteoporotic delayed vertebral fracture who underwent spinal surgery were enrolled at 6 hospitals. Sixty-five patients underwent AP surgery in 3 hospitals, and 28 patients underwent VP surgery in the other 3 hospitals. We restricted the spinal-fracture level to thoracolumbar lesion (T10–L2) and excluded patients followed up more than 2 years after surgery. The final numbers of patients included in this study were 24 in the AP group and 21 in the VP group. There were no significant differences between the 2 groups in terms of age, sex, disease duration, or duration of follow-up. From the *Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan; †Department of Orthopedic Surgery, Chubu Rosai Hospital, Nagoya, Japan; ‡Department of Orthopedic Surgery, Konan Kosei Hospital, Aichi, Japan; §Department of Orthopedic Surgery, Aichi Medical University, Aichi, Japan; ¶Department of Orthopedic Surgery, Nagano Red Cross Hospital, Nagano, Japan; Department of Orthopedic Surgery, Hamamatsu Medical Center, Shizuoka, Japan; and **Department of Orthopedic Surgery, Hamamatsu Medical University, Shizuoka, Japan. Acknowledgment date: May 30, 2014. First revision date: August 25, 2014. Acceptance date: August 30, 2014. The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. No relevant financial activities outside the submitted work. Address correspondence and reprint requests to Shiro Imagama MD, PhD, Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan, 65 Tsurumai, Showa-ku, Nagoya, Aichi 466-8560, Japan; E-mail: [email protected] DOI: 10.1097/BRS.0000000000000661
E120
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Results. Operative time was significantly longer and intraoperative blood loss significantly greater in the AP group. No significant difference between the 2 groups was observed in neurological improvement or the angle of kyphosis correction. However, the loss of correction was significantly greater in the VP group. There were no significant differences in perioperative respiratory or other complications. Implant-related complications and pseudarthrosis were more often observed in the VP group. One patient in the VP group underwent additional surgery for progression kyphosis. Conclusion. AP surgery provides stable spinal fixation and reduces implant failure particularly at the thoracolumbar junction because of load bearing of anterior spinal elements. Surgery-related complications in AP surgery were as few in number as with the VP group, and AP surgery is useful for osteoporotic delayed vertebral fracture. Key words: osteoporotic delayed vertebral fracture, anterior and posterior combined surgery, posterior fixation with vertebroplasty, osteoporosis, clinical outcome, minimally invasive surgery, thoracolumbar, fracture, geriatric people, neurological recovery, implant failure. Level of Evidence: 3 Spine 2015;40:E120–E126
O
steoporotic thoracolumbar compression fracture is becoming more common with the aging of the population.1,2 The majority of the patients with osteoporotic vertebral compression fracture are treated conservatively. However, delayed post-traumatic vertebral collapse after an acute thoracolumbar compression fracture sometimes occur.3,4 Delayed post-traumatic vertebral collapse is frequently associated with an intravertebral cleft, and this cleft is generally considered to be a sign of avascular necrosis of the vertebral body, known as Kummell disease.5 Secondary to Kummell disease, spinal column instability or aggravation of local kyphosis is often observed,6,7 and surgical treatment is highly recommended for patients with severe low back pain and/or neurological complications.8,9 January 2015
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. SPINE140715_LR E120
18/12/14 7:11 PM
SURGERY Various surgical procedures have been proposed in the management of osteoporotic delayed post-traumatic vertebral collapse. However, the optimal surgical procedures remain controversial because of aged patients’ numerous comorbid medical complications and frequent instrumentation failure secondary to low bone quality.9–11 Anterior instrumentation surgery using a vertebral spacer has been reported as an ideal method of surgery because of the direct resection of the retropulsed bony fragment and the reconstruction of the stable anterior spinal column.12,13 However, the anterior spinal fixation is not sufficient: it has been reported that additional posterior instrumentation surgery was also required in as many as 20% to 30% of cases because of progression of a kyphotic deformity or screw loosening within 3 months postoperatively.8,9 To avoid such unexpected additional surgery, some surgeons primarily opt for a combination of both anterior and posterior surgery. On the contrary, to minimize surgical invasiveness in aging patients, a 1-stage posterior instrumentation technique with vertebroplasty has also been tried, according to several reports.9,10,14 By augmentation of the anterior column using vertebroplasty, more rigid fixation was obtained with posterior instrumentation with vertebroplasty than with standard posterior fixation. It has been reported that this vertebroplasty technique improves angular deformity and reconstitution of body height, and that the instrumentation failure rate may be lower than it is without vertebroplasty. It is unclear, however, which is actually preferable: rigid fixation using a combination of anterior and posterior surgery— a surgical technique suspected of having a high complication rate because of their invasiveness—or minimally invasive surgery using posterior fusion with vertebroplasty, which carries the risk of instrumentation failure secondary to poor fixation in patients with low bone quality. As far as we know, there have been no reports to compare the 2 surgical results for osteoporotic delayed vertebral fracture. The purpose of this study was to compare the surgical results of anterior and posterior combined surgery (AP) and posterior fixation with vertebroplasty (VP) for treating osteoporotic delayed vertebral collapse, and provide a detailed analysis of the associated problems.
Osteoporotic Delayed Vertebral Fracture • Nakashima et al
from this study. Patients with degenerative spinal stenosis were defined as those that had a history of outpatient visits and spinal stenosis was diagnosed by radiographical and physical examinations.
Surgical Procedures and Patient Selection Anterior neural decompression and posterior fusion were performed on 65 patients (AP group), whereas posterior indirect neural decompression and short-segment spinal fusion combined with vertebroplasty were performed on 28 patients (VP group) (Figure 1). AP surgery was selected in 3 of the hospitals and VP surgery was selected in the other 3. To compare the 2 surgical procedures (AP and VP), we excluded those whose spinal-fracture level was not in the thoracolumbar lesion (T10–L2). The result was 37 patients in the AP group and 27 patients in the VP group. We then further excluded patients who were not followed up more than 2 years after surgery. The final numbers of patients included in this study were 24 in the AP group and 21 in the VP group. There were no significant differences between the 2 groups in terms of age, sex, illness duration, or duration of follow-up. Fusion length, however, was significantly longer in the VP group than in the AP group (Table 1).
Anterior and Posterior Combined Surgery (AP Group) The combined posterior-anterior procedure consisted of posterior fixation with a pedicle screw-and-hook system followed by anterior decompression and interbody fusion in the same anesthetic setting (Figure 2).15 First, posterior fixation was performed. Two pedicle screws and 1 hook were put in place at 1 level above and 1 level below the injured vertebra in prone position on a Hall frame. Next, the anterior procedure
MATERIALS AND METHODS Patient Population This study was a retrospective, multicenter study. Institutional review board approval was obtained for medical record review. Six hospitals in our spine group were included to this study. A total of 93 patients with osteoporotic delayed vertebral fracture who underwent spinal surgery were enrolled between 1997 and 2010. All patients with vertebral fractures were treated conservatively, and none had neurological deficits immediately after injury. Surgical treatment was indicated for the patients with progressive neurological deficits and/or continuous severe lower back pain caused by vertebral collapse. Patients with metastatic spinal tumors, degenerative spinal stenosis, and/or a previous spinal surgical history were excluded Spine
Figure 1. The schema of patient selection. Ninety-three patients were divided into 2 surgical-procedure groups (AP or VP) depending on the hospitals where their surgery was performed. The vertebral-fracture levels selected were only T11, T12, L1, and L2; in addition, only patients with more than 2-year follow-up were included in this study. AP indicates anterior and posterior combined surgery; VP, posterior fixation with vertebroplasty. www.spinejournal.com
E121
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. SPINE140715_LR E121
18/12/14 7:11 PM
SURGERY
Osteoporotic Delayed Vertebral Fracture • Nakashima et al
TABLE 1. Summary of Patient Background Data P
AP Group
VP Group
24
21
Sex (M/F)
5/19
6/15
0.73
Age (yr)
71.3
74.6
0.14
5.3 ± 4.2
5.3 ± 5.6
0.99
T11
1
2
T12
7
9
L1
16
10
L2
0
0
0.41
2.4 ± 0.9
3.1 ± 1.1
0.03*
No. of cases
Illness duration (mo) Affected vertebra
Fusion level F/u period (mo)
45.3 ± 21.2 39.8 ± 12.7
0.30
AP indicates anterior and posterior combined surgery; VP, posterior spinal fusion with vertebroplasty; M, male; F, female; F/u, follow-up.
was performed using the retroperitoneal or extrapleural approach, in the right decubitus position. The lateral and the anterior aspects of the injured vertebral body were exposed. The collapsed body including posterior wall was subtotally resected after removal of the discs above and below. When removing discs above and below, preserving the endplates is crucial for preventing postoperative correction loss, and so the procedure was performed here very carefully. After anterior decompression, anterior interbody fusion was performed using an anterior metal cage filled with cancellous bone chips harvested from the resected rib or the iliac crest.
Posterior Spinal Fusion With Vertebroplasty (VP Group) This surgery was performed using the standard posterior technique. Patients were placed prone on a radiolucent operating table (Figure 3). The kyphotic deformity was corrected mainly by postural reduction on the operating table, and no overcorrection was performed. Pedicle screws were placed promptly into the vertebrae 1 or 2 levels above and below the affected vertebra (1 level above and below in 9 patients; 2 levels above and below in 4 patients; 2 levels above and 2 levels below in 5 patients; and 3 levels above and 2 levels below in 3 patients). Tekmilon tape (an ultrahigh molecular weight polyethylene tape; Alfresa Pharma, Osaka, Japan) and laminae hooks were used in addition to obtain more rigid fixation, as shown in Figure 3. Posterior decompression (laminectomy) was performed at the affected vertebral body level. After adequate decompression, a 4.7- or 6-mm-diameter hole was made in the bilateral pedicle of the fractured vertebra initially with the pedicle probe. A cavity extending to the anterior vertebra was then created via both of the pedicles of the affected vertebra with some elevation. Once the cannula reached the center of the vertebral body, under continuous fluoroscopic monitoring, calcium phosphate cement (Taisho Pharmaceutical Co., Tokyo, Japan) was injected using a gun after curettage and further vertebral reduction. Posterolateral fusion with autogenous bone graft using local bone was then performed.
Postoperative Treatment An ambulation and rehabilitation program was started on the day of drain removal (usually 2 to 5 d after surgery). A body cast was used for 4 to 8 weeks postoperatively, and a custommade plastic thoracolumbosacral orthosis was used for about 3 months with 8 patients in the AP group. Only a custom
Figure 2. Representative case of anterior and posterior combined surgery. A 65-year-old-female patient who underwent anterior and posterior combined surgery for L1 osteoporotic vertebral collapse. Preoperative posteroanterior (A) and lateral (B) radiographs. Preoperative local kyphotic angle was 25º, and the angle was corrected to 8º after surgery. Postoperative posteroanterior (C) and lateral (D) radiographs taken 2 years after surgery. Loss of correction was 2º.
E122
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January 2015
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. SPINE140715_LR E122
18/12/14 7:11 PM
SURGERY
Osteoporotic Delayed Vertebral Fracture • Nakashima et al
Figure 3. Representative case of posterior fusion with vertebroplasty. A 65-year-old-female patient who underwent posterior decompression and pedicle screw instrumentation with vertebroplasty for an T12 osteoporotic vertebral collapse. Preoperative posteroanterior (A) and lateral (B) radiographs. Preoperative local kyphotic angle was 46º, and the angle was corrected to 34º after surgery (C, D). However, the local kyphotic angle 1.5 years after surgery was 45º for the loosening of proximal pedicle screws (E). Revision surgery was performed because of severe low back pain (F, G).
thoracolumbosacral orthosis was used (for about 3 mo) with the other patients.
Evaluation The clinical records were reviewed for operation time, intraoperative blood loss, complications, radiological, and neurological improvements. The neurological status of each patient was assessed using the Frankel Grade system. Preoperative radiological studies included plain radiography, computed tomography (CT), and magnetic resonance imaging. Radiographs were reviewed before surgery, 4 to 6 weeks after surgery, 1 year after surgery, 2 years after surgery and at the latest follow-up. The local kyphotic angle was measured between the upper surface of the vertebral body above the collapse and the lower surface of the vertebral body below on the lateral-view radiograph.16 Spine
Spinal canal encroachment due to retropulsed bony fragments was measured using CT scans obtained preoperatively and at the final follow-up. The extent of bony fragment encroachment in the spinal canal was calculated as the ratio (percentage) of the anteroposterior diameter of bony fragments to the anteroposterior diameter of the spinal canal.9 Pedicle screw loosening was confirmed using postoperative CT scans, and pedicle screw cutout was defined for the screws outside the pedicle. Postoperative adjacent vertebral fracture was confirmed using magnetic resonance image and radiographs. Postoperative fusion was evaluated using CT reconstruction scans. Existence of a clear radiolucent zone at the border area was confirmed on the CT reconstruction scans. Disappearance of the clear zone was interpreted as an indication of successful fusion. www.spinejournal.com
E123
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. SPINE140715_LR E123
18/12/14 7:11 PM
SURGERY
Osteoporotic Delayed Vertebral Fracture • Nakashima et al
Statistical Analysis Independent sample t tests and Fisher exact tests were conducted to compare the outcomes in the AP and VP groups. These statistical tests were 2-tailed, and a P < 0.05 was considered to be significant. Statistical analyses were conducted using SPSS version 17 (SPSS Inc, Chicago, IL).
TABLE 3. Kyphotic Angle and Spinal Canal
Encroachment Before and After Surgery AP Group
VP Group
P
22.8 ± 12.4
21.7 ± 10.6
0.78
Local kyphotic angle (°)
RESULTS
Preoperative
Comparison of Surgical Duration and Blood Loss
Immediate postoperative
6.7 ± 7.4
8.1 ± 9.2
0.74
1-yr postoperative
12.5 ± 8.7
17.0 ± 6.7
0.08
2-yr postoperative
13.1 ± 9.0
20.2 ± 7.2
0.006*
At final follow-up
13.7 ± 7.2
21.5 ± 9.3
0.003*
Correction
16.2 ± 9.1
13.5 ± 7.6
0.31
Loss of correction
7.0 ± 6.0
13.4 ± 7.3
0.003*
38.3 ± 18.4
31.9 ± 14.2
0.83
0
21.6 ± 8.6
SURGERY
Comparative Study of 2 Surgical Procedures for Osteoporotic Delayed Vertebral Collapse Anterior and Posterior Combined Surgery Versus Posterior Spinal Fusion With Vertebroplasty Hiroaki Nakashima, MD,* Shiro Imagama, MD, PhD,* Yasutsugu Yukawa, MD, PhD,† Tokumi Kanemura, MD, PhD,‡ Mitsuhiro Kamiya, MD, PhD,§ Masao Deguchi, MD, PhD,¶ Norimitsu Wakao, MD, PhD,§ Takashi Sato, MD,§ Kei Matsuzaki, MD,¶ Go Yoshida, MD, Yukihiro Matsuyama, MD, PhD,** Naoki Ishiguro, MD, PhD,* and Fumihiko Kato, MD†
Study Design. Retrospective comparative study. Objective. To compare the surgical results of anterior and posterior combined surgery (AP) and posterior fixation with vertebroplasty (VP) for treating osteoporotic delayed vertebral collapse. Summary of Background Data. The optimal treatment of osteoporotic delayed vertebral collapse has been controversial. Because of aged patients’ numerous comorbid medical complications and frequent instrumentation failure secondary to osteoporosis, it is challenging for surgeons to manage osteoporotic delayed vertebral collapse. In spite of this, there have been few reports comparing the surgical results. Methods. A total of 93 patients with osteoporotic delayed vertebral fracture who underwent spinal surgery were enrolled at 6 hospitals. Sixty-five patients underwent AP surgery in 3 hospitals, and 28 patients underwent VP surgery in the other 3 hospitals. We restricted the spinal-fracture level to thoracolumbar lesion (T10–L2) and excluded patients followed up more than 2 years after surgery. The final numbers of patients included in this study were 24 in the AP group and 21 in the VP group. There were no significant differences between the 2 groups in terms of age, sex, disease duration, or duration of follow-up. From the *Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan; †Department of Orthopedic Surgery, Chubu Rosai Hospital, Nagoya, Japan; ‡Department of Orthopedic Surgery, Konan Kosei Hospital, Aichi, Japan; §Department of Orthopedic Surgery, Aichi Medical University, Aichi, Japan; ¶Department of Orthopedic Surgery, Nagano Red Cross Hospital, Nagano, Japan; Department of Orthopedic Surgery, Hamamatsu Medical Center, Shizuoka, Japan; and **Department of Orthopedic Surgery, Hamamatsu Medical University, Shizuoka, Japan. Acknowledgment date: May 30, 2014. First revision date: August 25, 2014. Acceptance date: August 30, 2014. The manuscript submitted does not contain information about medical device(s)/drug(s). No funds were received in support of this work. No relevant financial activities outside the submitted work. Address correspondence and reprint requests to Shiro Imagama MD, PhD, Department of Orthopedic Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan, 65 Tsurumai, Showa-ku, Nagoya, Aichi 466-8560, Japan; E-mail: [email protected] DOI: 10.1097/BRS.0000000000000661
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Results. Operative time was significantly longer and intraoperative blood loss significantly greater in the AP group. No significant difference between the 2 groups was observed in neurological improvement or the angle of kyphosis correction. However, the loss of correction was significantly greater in the VP group. There were no significant differences in perioperative respiratory or other complications. Implant-related complications and pseudarthrosis were more often observed in the VP group. One patient in the VP group underwent additional surgery for progression kyphosis. Conclusion. AP surgery provides stable spinal fixation and reduces implant failure particularly at the thoracolumbar junction because of load bearing of anterior spinal elements. Surgery-related complications in AP surgery were as few in number as with the VP group, and AP surgery is useful for osteoporotic delayed vertebral fracture. Key words: osteoporotic delayed vertebral fracture, anterior and posterior combined surgery, posterior fixation with vertebroplasty, osteoporosis, clinical outcome, minimally invasive surgery, thoracolumbar, fracture, geriatric people, neurological recovery, implant failure. Level of Evidence: 3 Spine 2015;40:E120–E126
O
steoporotic thoracolumbar compression fracture is becoming more common with the aging of the population.1,2 The majority of the patients with osteoporotic vertebral compression fracture are treated conservatively. However, delayed post-traumatic vertebral collapse after an acute thoracolumbar compression fracture sometimes occur.3,4 Delayed post-traumatic vertebral collapse is frequently associated with an intravertebral cleft, and this cleft is generally considered to be a sign of avascular necrosis of the vertebral body, known as Kummell disease.5 Secondary to Kummell disease, spinal column instability or aggravation of local kyphosis is often observed,6,7 and surgical treatment is highly recommended for patients with severe low back pain and/or neurological complications.8,9 January 2015
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. SPINE140715_LR E120
18/12/14 7:11 PM
SURGERY Various surgical procedures have been proposed in the management of osteoporotic delayed post-traumatic vertebral collapse. However, the optimal surgical procedures remain controversial because of aged patients’ numerous comorbid medical complications and frequent instrumentation failure secondary to low bone quality.9–11 Anterior instrumentation surgery using a vertebral spacer has been reported as an ideal method of surgery because of the direct resection of the retropulsed bony fragment and the reconstruction of the stable anterior spinal column.12,13 However, the anterior spinal fixation is not sufficient: it has been reported that additional posterior instrumentation surgery was also required in as many as 20% to 30% of cases because of progression of a kyphotic deformity or screw loosening within 3 months postoperatively.8,9 To avoid such unexpected additional surgery, some surgeons primarily opt for a combination of both anterior and posterior surgery. On the contrary, to minimize surgical invasiveness in aging patients, a 1-stage posterior instrumentation technique with vertebroplasty has also been tried, according to several reports.9,10,14 By augmentation of the anterior column using vertebroplasty, more rigid fixation was obtained with posterior instrumentation with vertebroplasty than with standard posterior fixation. It has been reported that this vertebroplasty technique improves angular deformity and reconstitution of body height, and that the instrumentation failure rate may be lower than it is without vertebroplasty. It is unclear, however, which is actually preferable: rigid fixation using a combination of anterior and posterior surgery— a surgical technique suspected of having a high complication rate because of their invasiveness—or minimally invasive surgery using posterior fusion with vertebroplasty, which carries the risk of instrumentation failure secondary to poor fixation in patients with low bone quality. As far as we know, there have been no reports to compare the 2 surgical results for osteoporotic delayed vertebral fracture. The purpose of this study was to compare the surgical results of anterior and posterior combined surgery (AP) and posterior fixation with vertebroplasty (VP) for treating osteoporotic delayed vertebral collapse, and provide a detailed analysis of the associated problems.
Osteoporotic Delayed Vertebral Fracture • Nakashima et al
from this study. Patients with degenerative spinal stenosis were defined as those that had a history of outpatient visits and spinal stenosis was diagnosed by radiographical and physical examinations.
Surgical Procedures and Patient Selection Anterior neural decompression and posterior fusion were performed on 65 patients (AP group), whereas posterior indirect neural decompression and short-segment spinal fusion combined with vertebroplasty were performed on 28 patients (VP group) (Figure 1). AP surgery was selected in 3 of the hospitals and VP surgery was selected in the other 3. To compare the 2 surgical procedures (AP and VP), we excluded those whose spinal-fracture level was not in the thoracolumbar lesion (T10–L2). The result was 37 patients in the AP group and 27 patients in the VP group. We then further excluded patients who were not followed up more than 2 years after surgery. The final numbers of patients included in this study were 24 in the AP group and 21 in the VP group. There were no significant differences between the 2 groups in terms of age, sex, illness duration, or duration of follow-up. Fusion length, however, was significantly longer in the VP group than in the AP group (Table 1).
Anterior and Posterior Combined Surgery (AP Group) The combined posterior-anterior procedure consisted of posterior fixation with a pedicle screw-and-hook system followed by anterior decompression and interbody fusion in the same anesthetic setting (Figure 2).15 First, posterior fixation was performed. Two pedicle screws and 1 hook were put in place at 1 level above and 1 level below the injured vertebra in prone position on a Hall frame. Next, the anterior procedure
MATERIALS AND METHODS Patient Population This study was a retrospective, multicenter study. Institutional review board approval was obtained for medical record review. Six hospitals in our spine group were included to this study. A total of 93 patients with osteoporotic delayed vertebral fracture who underwent spinal surgery were enrolled between 1997 and 2010. All patients with vertebral fractures were treated conservatively, and none had neurological deficits immediately after injury. Surgical treatment was indicated for the patients with progressive neurological deficits and/or continuous severe lower back pain caused by vertebral collapse. Patients with metastatic spinal tumors, degenerative spinal stenosis, and/or a previous spinal surgical history were excluded Spine
Figure 1. The schema of patient selection. Ninety-three patients were divided into 2 surgical-procedure groups (AP or VP) depending on the hospitals where their surgery was performed. The vertebral-fracture levels selected were only T11, T12, L1, and L2; in addition, only patients with more than 2-year follow-up were included in this study. AP indicates anterior and posterior combined surgery; VP, posterior fixation with vertebroplasty. www.spinejournal.com
E121
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. SPINE140715_LR E121
18/12/14 7:11 PM
SURGERY
Osteoporotic Delayed Vertebral Fracture • Nakashima et al
TABLE 1. Summary of Patient Background Data P
AP Group
VP Group
24
21
Sex (M/F)
5/19
6/15
0.73
Age (yr)
71.3
74.6
0.14
5.3 ± 4.2
5.3 ± 5.6
0.99
T11
1
2
T12
7
9
L1
16
10
L2
0
0
0.41
2.4 ± 0.9
3.1 ± 1.1
0.03*
No. of cases
Illness duration (mo) Affected vertebra
Fusion level F/u period (mo)
45.3 ± 21.2 39.8 ± 12.7
0.30
AP indicates anterior and posterior combined surgery; VP, posterior spinal fusion with vertebroplasty; M, male; F, female; F/u, follow-up.
was performed using the retroperitoneal or extrapleural approach, in the right decubitus position. The lateral and the anterior aspects of the injured vertebral body were exposed. The collapsed body including posterior wall was subtotally resected after removal of the discs above and below. When removing discs above and below, preserving the endplates is crucial for preventing postoperative correction loss, and so the procedure was performed here very carefully. After anterior decompression, anterior interbody fusion was performed using an anterior metal cage filled with cancellous bone chips harvested from the resected rib or the iliac crest.
Posterior Spinal Fusion With Vertebroplasty (VP Group) This surgery was performed using the standard posterior technique. Patients were placed prone on a radiolucent operating table (Figure 3). The kyphotic deformity was corrected mainly by postural reduction on the operating table, and no overcorrection was performed. Pedicle screws were placed promptly into the vertebrae 1 or 2 levels above and below the affected vertebra (1 level above and below in 9 patients; 2 levels above and below in 4 patients; 2 levels above and 2 levels below in 5 patients; and 3 levels above and 2 levels below in 3 patients). Tekmilon tape (an ultrahigh molecular weight polyethylene tape; Alfresa Pharma, Osaka, Japan) and laminae hooks were used in addition to obtain more rigid fixation, as shown in Figure 3. Posterior decompression (laminectomy) was performed at the affected vertebral body level. After adequate decompression, a 4.7- or 6-mm-diameter hole was made in the bilateral pedicle of the fractured vertebra initially with the pedicle probe. A cavity extending to the anterior vertebra was then created via both of the pedicles of the affected vertebra with some elevation. Once the cannula reached the center of the vertebral body, under continuous fluoroscopic monitoring, calcium phosphate cement (Taisho Pharmaceutical Co., Tokyo, Japan) was injected using a gun after curettage and further vertebral reduction. Posterolateral fusion with autogenous bone graft using local bone was then performed.
Postoperative Treatment An ambulation and rehabilitation program was started on the day of drain removal (usually 2 to 5 d after surgery). A body cast was used for 4 to 8 weeks postoperatively, and a custommade plastic thoracolumbosacral orthosis was used for about 3 months with 8 patients in the AP group. Only a custom
Figure 2. Representative case of anterior and posterior combined surgery. A 65-year-old-female patient who underwent anterior and posterior combined surgery for L1 osteoporotic vertebral collapse. Preoperative posteroanterior (A) and lateral (B) radiographs. Preoperative local kyphotic angle was 25º, and the angle was corrected to 8º after surgery. Postoperative posteroanterior (C) and lateral (D) radiographs taken 2 years after surgery. Loss of correction was 2º.
E122
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January 2015
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. SPINE140715_LR E122
18/12/14 7:11 PM
SURGERY
Osteoporotic Delayed Vertebral Fracture • Nakashima et al
Figure 3. Representative case of posterior fusion with vertebroplasty. A 65-year-old-female patient who underwent posterior decompression and pedicle screw instrumentation with vertebroplasty for an T12 osteoporotic vertebral collapse. Preoperative posteroanterior (A) and lateral (B) radiographs. Preoperative local kyphotic angle was 46º, and the angle was corrected to 34º after surgery (C, D). However, the local kyphotic angle 1.5 years after surgery was 45º for the loosening of proximal pedicle screws (E). Revision surgery was performed because of severe low back pain (F, G).
thoracolumbosacral orthosis was used (for about 3 mo) with the other patients.
Evaluation The clinical records were reviewed for operation time, intraoperative blood loss, complications, radiological, and neurological improvements. The neurological status of each patient was assessed using the Frankel Grade system. Preoperative radiological studies included plain radiography, computed tomography (CT), and magnetic resonance imaging. Radiographs were reviewed before surgery, 4 to 6 weeks after surgery, 1 year after surgery, 2 years after surgery and at the latest follow-up. The local kyphotic angle was measured between the upper surface of the vertebral body above the collapse and the lower surface of the vertebral body below on the lateral-view radiograph.16 Spine
Spinal canal encroachment due to retropulsed bony fragments was measured using CT scans obtained preoperatively and at the final follow-up. The extent of bony fragment encroachment in the spinal canal was calculated as the ratio (percentage) of the anteroposterior diameter of bony fragments to the anteroposterior diameter of the spinal canal.9 Pedicle screw loosening was confirmed using postoperative CT scans, and pedicle screw cutout was defined for the screws outside the pedicle. Postoperative adjacent vertebral fracture was confirmed using magnetic resonance image and radiographs. Postoperative fusion was evaluated using CT reconstruction scans. Existence of a clear radiolucent zone at the border area was confirmed on the CT reconstruction scans. Disappearance of the clear zone was interpreted as an indication of successful fusion. www.spinejournal.com
E123
Copyright © 2015 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. SPINE140715_LR E123
18/12/14 7:11 PM
SURGERY
Osteoporotic Delayed Vertebral Fracture • Nakashima et al
Statistical Analysis Independent sample t tests and Fisher exact tests were conducted to compare the outcomes in the AP and VP groups. These statistical tests were 2-tailed, and a P < 0.05 was considered to be significant. Statistical analyses were conducted using SPSS version 17 (SPSS Inc, Chicago, IL).
TABLE 3. Kyphotic Angle and Spinal Canal
Encroachment Before and After Surgery AP Group
VP Group
P
22.8 ± 12.4
21.7 ± 10.6
0.78
Local kyphotic angle (°)
RESULTS
Preoperative
Comparison of Surgical Duration and Blood Loss
Immediate postoperative
6.7 ± 7.4
8.1 ± 9.2
0.74
1-yr postoperative
12.5 ± 8.7
17.0 ± 6.7
0.08
2-yr postoperative
13.1 ± 9.0
20.2 ± 7.2
0.006*
At final follow-up
13.7 ± 7.2
21.5 ± 9.3
0.003*
Correction
16.2 ± 9.1
13.5 ± 7.6
0.31
Loss of correction
7.0 ± 6.0
13.4 ± 7.3
0.003*
38.3 ± 18.4
31.9 ± 14.2
0.83
0
21.6 ± 8.6
