Abstract
Background:
Percutaneous pedicle screw (PPS) fixation has been introduced into palliative surgery for metastatic spine tumors; however, the therapeutic effects of PPS on the outcomes of multidisciplinary treatment for such tumors are unclear. Therefore, the therapeutic impact of PPS was investigated among patients with metastatic spine tumors and with revised Tokuhashi scores of ≤8.
Materials and Methods:
A total of 47 patients who underwent conventional palliative surgery (posterior decompression and stabilization, 33; posterior stabilization alone, 14) before the introduction of PPS and 38 patients who underwent PPS (posterior decompression and stabilization, 19; posterior stabilization alone, 19) were included. Surgical stress (operative time, blood loss, complications, etc.) and treatment outcomes (postoperative survival time, visual analog scale scores, Frankel classification, and the Barthel index at the final followup) were compared between the conventional and PPS groups.
Results:
The age of the indicated patients significantly increased after the introduction of PPS (P < 0.05). Regarding posterior decompression and stabilization, there were no significant intergroup differences in surgical stress or treatment outcomes. As for posterior stabilization alone, there were significant preoperative differences in various parameters between the conventional and PPS groups (P < 0.01) and also significant postoperative intergroup differences between surgical stress and treatment outcomes (P < 0.01).
Conclusions:
For patients with early-stage metastatic spine tumors, the use of PPS-based posterior stabilization combined with multidisciplinary adjuvant therapy has changed the age range of the patients indicated for surgery and caused significant improvements in surgical stress, postoperative survival time, and Barthel index.
Keywords: Metastatic spine tumor, outcome, palliative surgery, percutaneous pedicle screw fixation, survival time
Introduction
Patients with metastatic spine tumors often experience severe pain due to spinal instability, and the associated spinal cord compression can also cause paralysis. The incidence of metastatic tumor-induced spinal cord compression is not low, i.e., it occurs in 5%–14% of all cancer patients.1,2 It has been reported that recovery from complete spinal cord paralysis is difficult to achieve, and so, metastatic tumor-induced spinal cord paralysis should be treated as quickly as possible before it becomes severe.3,4,5 Patchell et al.2 and Cole and Patchell6 reported that direct decompressive surgery is more effective at ameliorating such paralysis than radiotherapy. In addition, spinal stabilization to treat instability or spinal cord compression by an epidural tumor helps to reduce pain and improves patients' quality of life.7,8,9,10,11,12 Therefore, stabilization surgery with or without direct decompression plays a very important role in palliative treatment for spine tumors.
Percutaneous pedicle screw (PPS) fixation is a surgical procedure in which pedicle screws are percutaneously inserted into multiple vertebrae and fixed between rods through the subcutaneous paravertebral muscle. PPS fixation has been reported to be effective and to involve reduced levels of surgical stress.13,14,15,16 In addition, PPS results in superior wound healing than conventional posterior stabilization, and the incidence of postoperative infections is low after PPS. Another benefit of PPS is that patients can start radiotherapy and chemotherapy early.17 Therefore, PPS is a suitable surgical procedure for achieving palliative spinal stabilization with or without decompression.18
Recently, PPS has been increasingly used as a palliative procedure for metastatic spine tumors. However, as significant bleeding sometimes occurs when decompression is combined with PPS, there is a question about whether PPS cause less surgical stress than conventional stabilization with decompression.18 Further, it is unclear whether the ability to start adjuvant therapy early due to the reduction in surgical stress associated with the procedure represents a treatment outcome. In other words, the effects of introduction of PPS on the outcomes of palliative surgery for metastatic spine tumors are still unclear. Thus, we investigated the therapeutic impact of PPS on palliative surgery for metastatic spine tumors.
Materials and Methods
Subjects
The subjects were patients with metastatic spine tumors and with revised Tokuhashi scores [Table 1] of ≤819 who were indicated for palliative surgery and had predicted life expectancies of ≤6 months. As the participants were limited to patients with revised Tokuhashi scores of ≤8,19 the severity of the disease was similar in each case.
Table 1.
Revised Tokuhashi score
| Predictive factor | Score (points) |
|---|---|
| General condition | |
| Poor (KPS 10%-40%) | 0 |
| Moderate (KPS 50%-70%) | 1 |
| Good (KPS 80%-100%) | 2 |
| Number of extraspinal bone metastases foci | |
| ≥3 | 0 |
| 1-2 | 1 |
| 0 | 2 |
| Number of metastases in the vertebral body | |
| ≥3 | 0 |
| 2 | 1 |
| 1 | 2 |
| Metastases to the major internal organs | |
| Unremovable | 0 |
| Removable | 1 |
| No metastases | 2 |
| Primary site of the cancer | |
| Lung, osteosarcoma, stomach, bladder, esophagus, pancreas | 0 |
| Liver, gallbladder, unidentified | 1 |
| Others | 2 |
| Kidney, uterus | 3 |
| Rectum | 4 |
| Thyroid, prostate, breast, carcinoid tumor | 5 |
| Spinal cord palsy | |
| Complete (Frankel A, B) | 0 |
| Incomplete (Frankel C, D) | 1 |
| None (Frankel E) | 2 |
| Total points | Predicted prognosis |
| 0-8 | <6 months |
| 9-11 | ≥6 months |
| 12-15 | ≥1 year |
KPS indicates Karnofsky’s performance status. The expected survival period was<6 months when the total score was 0-8, 6 months or longer when the total score was 9-11, and 1 year or longer when the total score was 12 or higher
They included 47 patients who were treated with the conventional procedure before the introduction of PPS (from 2007 to 2012; the conventional group) and 38 PPS-treated patients (from 2012 to 2017; the PPS group). In the palliative surgery, a combination of posterior decompression and posterior stabilization was performed although some patients were treated with posterior stabilization alone. As for the implants employed, the XIA® and DIAPASON® (Stryker Co., Kalamazoo, USA) were used in the conventional procedure, whereas the MANTIS® and ES2® (Stryker Co., Kalamazoo, USA) were used for the PPS.
Patients with tumor-induced paralysis and spinal cord compression were indicated for posterior decompression and stabilization, which was considered to be the first-choice procedure, providing circumstances permitted it. Patients with no or slight paralysis whose spinal support needed to be reconstructed or maintained were indicated for posterior stabilization alone. Sometimes, the latter procedure was indicated when decompression of the spinal cord could not be conducted due to the circumstances of the case, such as the patient's general condition. Adjuvant therapy (chemotherapy before or after surgery or local radiotherapy after surgery) and bone-modifying agents were administered without restriction based on the patients' wishes.
The study protocol was approved by our institutional ethics committee (approval number: RK-11209-8). Informed consent was obtained from all patients.
Epidural spinal cord compression scale
The epidural spinal cord compression (ESCC) scale20 consists of six grades: grade 0, bone involvement alone; Grade 1, epidural impingement; Grade 2, the retention of cerebrospinal fluid (CSF) is visible despite spinal cord compression; and Grade 3, CSF is not visible due to marked spinal cord compression. Grade 1 is classified into three subgroups: grade 1a, epidural impingement without deformation of the thecal sac; Grade 1b, compression of the thecal sac without spinal cord abutment; and Grade 1c, deformation of the thecal sac with spinal cord abutment in the absence of spinal cord compression.
Preoperative background
The patients' background data are presented according to the procedure performed in Tables 1 and 2. Among the patients who underwent posterior decompression and stabilization, there was no significant intergroup difference in the sex ratio, but the age of the patients who were indicated for surgery was significantly higher in the PPS group (P = 0.0412). No significant difference in the type of primary cancer, affected level (symptomatic level), revised Tokuhashi score [Table 1],19,21 visual analog scale (VAS) pain score,22,23,24 ESCC scale,20 Frankel classification,25 Barthel index,26 or frequency of adjuvant therapy was noted between the conventional and PPS groups [Table 2].
Table 2.
Background of the 52 patients with posterior decompression and stabilization
| Conventional group (n=33) | PPS group (n=19) | P | |
|---|---|---|---|
| Sex (male:female) | 24:9 | 15:4 | 0.6227 |
| Age (years), mean | 59.6±13.8 | 66.3±9.20 | 0.0412* |
| Primary site of the cancer, n (%) | |||
| Lung | 14 (42.4) | 5 (26.3) | 0.3061 |
| Liver | 2 (6.1) | 5 (26.3) | |
| Stomach | 1 (3.0) | 2 (10.5) | |
| Kidney | 3 (9.1) | 0 | |
| Breast | 2 (6.1) | 1 (5.3) | |
| Osteosarcoma | 1 (3.0) | 0 | |
| Pancreas | 1 (3.0) | 0 | |
| Colon | 1 (3.0) | 1 (5.3) | |
| Thyroid | 0 | 1 (5.3) | |
| Unknown | 2 (6.1) | 0 | |
| Others | 6 (18.2) | 4 (21.1) | |
| Affected lesion, n (%) | |||
| Thoracic | 29 (87.9) | 12 (63.2) | 0.1565 |
| Lumbosacral | 4 (12.1) | 6 (31.6) | |
| Revised Tokuhashi score, mean | 5.9±1.6 | 5.0±2.3 | 0.1516 |
| Preoperative VAS, mean (range) | 79.5±8.3 (38-100) | 76.5±10.2 (29-100) | 0.5021 |
| Preoperative ESCC scale, n (%) | |||
| 1a | 1 (3.0) | 1 (5.2) | 0.061 |
| 1b | 2 (6.1) | 0 | |
| 1c | 5 (15.2) | 0 | |
| 2 | 13 (39.4) | 7 (36.8) | |
| 3 | 12 (36.4) | 11 (57.9) | |
| Preoperative Frankel classification, n (%) | |||
| A | 1 (3.0) | 0 | 0.1176 |
| B | 6 (18.2) | 1 (5.2) | |
| C | 18 (54.5) | 11 (57.9) | |
| D | 5 (15.2) | 3 (15.8) | |
| E | 3 (9.1) | 4 (21.1) | |
| Preoperative Barthel index, mean (range) | 47.7±27.6 (5-85) | 49.9±22.9 (20-90) | 0.7556 |
| Adjuvant therapy, n (%) | |||
| Chemotherapy | 12 (36.4) | 11 (57.9) | 0.233462 |
| Radiation therapy | 15 (45.5) | 4 (21.1) | |
| Only care | 11 (33.3) | 6 (31.6) | |
| Bone modifying agent, n (%) | 22 (66.7) | 19 (100) |
*Significant differences. Conventional group indicates conventional procedure, PPS group, PPS was applied, VAS=Visual analog scale, ESCC=Epidural spinal cord compression, PPS=Percutaneous pedicle screw
On the other hand, among the patients who underwent posterior stabilization alone, there were significant differences in age, VAS pain score, ESCC scale, Frankel classification, Barthel index, and frequency of adjuvant therapy between the conventional and PPS groups [Table 3].
Table 3.
Background of the 33 patients with posterior stabilization
| Conventional group (n=14) | PPS group (n=19) | P | |
|---|---|---|---|
| Sex (male:female) | 8:6 | 14:5 | 0.3377 |
| Age (years), mean | 55.3±14.7 | 69.1±9.3 | 0.0055* |
| Primary site of the cancer, n (%) | |||
| Lung | 2 (14.3) | 9 (47.4) | 0.1037 |
| Liver | 1 (7.1) | 4 (21.1) | |
| Stomach | 0 | 1 (5.3) | |
| Kidney | 0 | 0 | |
| Breast | 3 (21.4) | 1 (5.3) | |
| Osteosarcoma | 1 (7.1) | 1 (5.3) | |
| Pancreas | 0 | 1 (5.3) | |
| Colon | 1 (7.1) | 1 (5.3) | |
| Thyroid | 0 | 1 (5.3) | |
| Unknown | 4 (28.6) | 0 | |
| Others | 2 (14.3) | 0 | |
| Affected lesion, n (%) | |||
| Thoracic | 9 (64.3) | 7 (36.8) | 0.1190 |
| Lumbosacral | 5 (35.7) | 12 (63.2) | |
| Revised Tokuhashi score, mean | 4.9±2.2 | 5.7±1.7 | 0.3299 |
| Preoperative VAS, mean (range) | 76.5±9.9 (30-100) | 79.4±8.4 (39-100) | 0.4982 |
| Preoperative ESCC scale, n (%) | |||
| 1a | 0 | 5 (26.3) | <0.001* |
| 1b | 1 (7.1) | 4 (21.1) | |
| 1c | 2 (14.3) | 4 (21.1) | |
| 2 | 3 (21.4) | 4 (21.1) | |
| 3 | 8 (57.1) | 2 (10.5) | |
| Preoperative Frankel classification, n (%) | |||
| A | 1 (3.0) | 0 | <0.001* |
| B | 4 (18.2) | 0 | |
| C | 6 (54.5) | 1 (5.3) | |
| D | 1 (15.2) | 9 (47.4) | |
| E | 2 (9.1) | 9 (47.4) | |
| Preoperative Barthel index, mean (range) | 37.1±17.8 (15-60) | 65.8±19.9 (10-100) | 0.0028* |
| Adjuvant therapy, n (%) | |||
| Chemotherapy | 4 (18.2) | 10 (52.6) | 0.0027* |
| Radiation therapy | 5 (35.7) | 9 (47.4) | |
| Only care | 4 (18.2) | 0 | |
| Bone modifying agent, n (%) | 2 (14.3) | 19 (100) |
*Significant differences. Conventional group indicates conventional procedure, PPS group, PPS was applied, VAS=Visual analog scale, ESCC=Epidural spinal cord compression, PPS=Percutaneous pedicle screw
Outcome assessment
The surgical stress associated with and treatment outcomes of (1) posterior decompression and stabilization and (2) posterior stabilization alone were investigated in the conventional and PPS groups. The numbers of immobilized and decompressed intervertebral segments, operative time, and amount of intraoperative blood loss were investigated as surgical stress parameters. As for treatment outcomes, the postoperative survival time, VAS pain score, severity of paralysis (Frankel classification), and rate of improvement in the Barthel index (as an index of the subjects' ability to perform activities of daily living [ADL]) at the final postoperative followup (the Barthel index was evaluated at regular intervals until death) were assessed.
Ethics
Institutional review board approval was obtained from Nihon University Itabashi Hospital (RK-11209-8).
Statistical analysis
For comparisons between pairs of items or groups, the t-test, Welch's method, paired t-test, or Mann–Whitney U-test was used. Survival rates were calculated using the Kaplan–Meier method and analyzed using the log-rank test. Statistical analyses were performed using StatMate V® (Atoms Co.; Tokyo, Japan), and P < 0.05 was regarded as statistically significant.
Results
Posterior decompression and stabilization
Surgical stress
The number of instrumented and decompressed segments did not differ significantly between the conventional and PPS groups. In addition, there were no significant differences in the operating time, amount of intraoperative blood loss, transfusion use, or frequency of perioperative complications between the conventional and PPS groups (P > 0.05) [Table 4].
Table 4.
Operative and outcome data comparing among posterior decompression and stabilization
| Conventional group (n=33) | PPS group (n=19) | P | |
|---|---|---|---|
| Instrumented segments, mean (range) | 5.5±2.1 (2-12) | 6.5±2.1 (4-11) | 0.1469 |
| Decompressed segments, mean (range) | 2.0±0.8 (1-4) | 2.1±1.1 (1-5) | 0.8558 |
| Operating time (min) | 227.8±51.9 | 253.7±54.4 | 0.1159 |
| Blood loss (g) | 694.5±926.3 | 528.7±486.4 | 0.4481 |
| Transfusion, n (%) | 11 (33.3) | 2 (10.5) | 0.0674 |
| Perioperative complications, n (%) | |||
| Wound infection | 2 (6.1) | 1 (5.3) | 0.6784 |
| Dural tear | 2 (6.1) | 1 (5.3) | |
| Neurological complication | 2 (6.1) | 1 (5.3) | |
| Lung infection/complications | 1 (3.0) | 1 (5.3) | |
| Brain infarct/complications | 1 (3.0) | 0 | |
| Instrumentation failure/complications | 0 | 0 | |
| Survival time, mean (range), months | 6.7±5.6 (0.6-21) | 6.8±6.1 (0.6-20) | 0.9568 |
| Postoperative VAS, mean (range) | 26.3±10.8 (0-52) | 23.5±8.5 (0-45) | 0.6234 |
| Postoperative Frankel classification, n (%) | |||
| A | 5 (15.2) | 0 | 0.0610 |
| B | 10 (30.3) | 4 (12.1) | |
| C | 4 (12.1) | 4 (12.1) | |
| D | 8 (24.2) | 4 (27.2) | |
| E | 6 (18.2) | 7 (48.4) | |
| Postoperative Barthel index, mean (range) | 67.6±27.7 (10-100) | 64.7±31.9 (15-100) | 0.7519 |
| Discharge to home, n (%) | 12 (36.4) | 6 (31.6) | 0.5300 |
*Significant differences. Conventional group indicates conventional procedure, PPS group, PPS was applied, VAS=Visual analog scale, PPS=Percutaneous pedicle screw
Treatment outcomes
The mean postoperative survival time did not differ significantly between the conventional and PPS groups (P = 0.9568) [Table 3], and no significant intergroup difference in the survival rate was noted (P = 0.4242, log-rank test) [Figure 1].
Figure 1.
Survival analyses of patients that underwent posterior decompression and stabilization based on Kaplan–Meier plots. In the log-rank test, no significant difference was noted between the two groups (P = 0.4242). Conventional group, the patients treated with the conventional procedure before the introduction of percutaneous pedicle screw fixation (PPS); PPS group, the PPS-treated patients. PPS = Percutaneous pedicle screw fixation
Pain was evaluated using a VAS. Significant improvements in the subjects' pain scores were noted after surgery (P < 0.001 in both groups). No significant intergroup difference in the pain score was detected at the final postoperative followup (pain was evaluated at regular intervals until death) (P = 0.6234) [Table 4].
The severity of paralysis was assessed using the Frankel classification. The postoperative severity of paralysis did not differ significantly between the two groups, as was found before surgery (P = 0.0610) [Table 4].
The subjects' ability to perform ADL was examined using the Barthel index. It was significantly improved after surgery in both groups (P < 0.001), and no significant intergroup difference in the final Barthel index was noted (P = 0.7519) [Table 4].
In total, 36.4% and 31.6% of the patients were discharged home after surgery in the conventional group and PPS group, respectively (P = 0.5300) [Table 4].
Posterior stabilization alone
Surgical stress
The number of instrumented and decompressed segments did not differ significantly between the conventional and PPS groups. The operating time was significantly longer in the PPS group than in the conventional group (P < 0.001). On the other hand, although transfusion use did not differ significantly between the groups, significantly less intraoperative blood loss occurred in the PPS group than in the conventional group (P < 0.001). No significant difference was noted in the incidence or type of surgical complications (P = 0.2964) [Table 5].
Table 5.
Operative and outcome data comparing among posterior stabilization
| Conventional group (n=14) | PPS group (n=19) | P | |
|---|---|---|---|
| Instrumented segments, mean (range) | 5.1±1.7 (2-12) | 6.1±3.1 (4-11) | 0.1482 |
| Operating time (min) | 133.6±11.1 | 194.3±64.5 | <0.001* |
| Blood loss (g) | 372.4±127.1 | 125.2±152.6 | <0.001* |
| Transfusion, n (%) | 1 (7.1) | 0 | 0.2368 |
| Perioperative complications, n (%) | |||
| Wound infection | 0 | 1 (5.3) | 0.2964 |
| Dural tear | 0 | 0 | |
| Neurological complication | 0 | 0 | |
| Lung infection/complications | 0 | 0 | |
| Brain infarct/complications | 0 | 0 | |
| Instrumentation failure/complications | 0 | 2 (10.5) | |
| Survival periods, mean (range), months | 3.7±2.3 (0.3-7) | 8.3±6.4 (0.3-27) | <0.001* |
| Postoperative VAS, mean (range) | 23.8±10.7 (0-44) | 26.5±9.5 (0-49) | 0.5632 |
| Postoperative Frankel classification, n (%) | |||
| A | 2 (14.3) | 0 | <0.001* |
| B | 6 (42.9) | 0 | |
| C | 3 (21.4) | 1 (5.3) | |
| D | 0 | 7 (36.8) | |
| E | 3 (21.4) | 11 (57.9) | |
| Postoperative Barthel index, mean (range) | 47.9±25.3 (15-85) | 82.4±26.8 (0-100) | 0.0070* |
| Discharge to home, n (%) | 4 (28.6) | 13 (68.4) | 0.0717 |
*Significant differences. Conventional group indicates conventional procedure, PPS group, PPS was applied, VAS=Visual analog scale, PPS=Percutaneous pedicle screw
Treatment outcomes
Although the preoperative revised Tokuhashi score did not differ significantly between the groups, the mean postoperative survival time was longer in the PPS group than in the conventional group (P < 0.001) [Table 5]. The survival rates of the two groups also differed significantly (P = 0.00178, log-rank test) [Figure 2].
Figure 2.
Survival analyses of patients that underwent posterior stabilization alone based on Kaplan–Meier plots. In the log-rank test, a significant difference was noted between the two groups (P = 0.00178). Conventional group, the patients treated with the conventional procedure before the introduction of PPS; PPS group, the PPS-treated patients. PPS = Percutaneous pedicle screw fixation
Significant improvements in the pain score were seen in both groups after surgery (P < 0.001 in both groups). No significant intergroup difference was noted in the pain score at the final postoperative followup (the subjects' pain scores were measured at regular intervals until death) (P = 0.5632) [Table 5].
It was difficult to compare the degree of improvement in paralysis between the groups because the state of paralysis and the ESCC scale differed significantly between the groups before surgery (P < 0.001) [Table 3]. The postoperative severity of paralysis differed significantly between the two groups as was found before surgery (P < 0.001) [Table 5].
It was also difficult to compare the degree of improvement in the Barthel index between the two groups because the preoperative Barthel indices of the two groups differed significantly (P = 0.0028) [Table 3]. The Barthel index improved significantly after surgery in both groups (conventional group: P =0.0228, PPS group: P <0.001). The Barthel index of the PPS group at the final postoperative followup (it was evaluated at regular intervals until death) was 82.4 ± 26.8, which was significantly different from that of the conventional group (P = 0.0070) [Table 5 and Figure 3].
Figure 3.
Change in the Barthel index after posterior stabilization. The Barthel index improved significantly after surgery in both groups (P < 0.001). A significant difference in the final Barthel index was noted between the two groups (P = 0.0070). PPS = Percutaneous pedicle screw
In total, 28.6% and 68.4% of patients were discharged home after surgery in the conventional group and PPS group, respectively (P = 0.0717) [Table 5].
Discussion
The use of PPS-based posterior stabilization alone combined with multidisciplinary adjuvant therapy to treat patients with early-stage metastatic spine tumors resulted in improvements in the level of surgical stress, age range of the patients indicated for surgery, postoperative survival time, and Barthel index. PPS was initially used during external fixation of the spine by Jeanneret and Magerl in 1982,27 and Foley et al. reported a system for performing percutaneous fixation (from screw insertion to the connection of the rod through a small incision) in 2001.28 Systems for percutaneously fixing multiple intervertebral segments have since become commercially available and have been used in the clinical setting.
Reductions in intraoperative blood loss and muscle damage can be achieved by performing PPS as it makes it possible to immobilize multiple intervertebral segments without dissecting the paraspinal muscles from the laminae. As for the disadvantages of PPS, it is difficult to carry out sufficient bone grafting via the posterior approach because the zygapophyseal joint cannot be exposed using this procedure, the cervicothoracic junction cannot be readily observed under fluoroscopy, and the resultant spinal cord decompression is likely to be insufficient. Therefore, this minimally invasive procedure, which is capable of immediately stabilizing the spine, is best for patients that are indicated for palliative surgery, who do not require long term spinal stability because of their limited life expectancy. It has been reported that surgical spinal cord decompression and stabilization followed by radiotherapy are effective at aiding recovery from paralysis.2,29 Furthermore, the risk of wound-related complications is low in PPS-treated cases, and radiotherapy can be initiated early after surgery involving PPS.
Therefore, the advantages of this method exceed its disadvantages for patients with metastatic spine tumors who have limited life expectancies. Maintaining quality of life using minimally invasive surgery has been reported to be important for patients with short life expectancies.30,31 However, the effects of the introduction of PPS on the outcomes of such treatment in patients with metastatic spine tumors are still unclear.17
In the present study, posterior decompression and stabilization did not result in a significant reduction in surgical stress. Basically, the spinal cord decompression and tumor curettage procedures have not been changed by the introduction of PPS, and this reality must not be ignored when considering surgery for metastatic spine tumors. On the other hand, the introduction of PPS has resulted in a significant expansion of the age range of the patients indicated for palliative surgery for metastatic spine tumors.
Among the patients who underwent posterior stabilization alone in the current study, there were significant preoperative differences in the VAS score, ESCC scale, Frankel classification, Barthel index, and frequency of adjuvant therapy between the conventional and PPS groups [Table 3]. Therefore, it was not possible to perform simple intergroup comparisons. That is to say, among the patients who were treated with posterior stabilization alone, pain, spinal cord compression, paralysis, and disturbances of ADL were significantly less severe in the PPS group than in the conventional group. In addition, the PPS group received more intensive adjuvant treatment than the conventional group. In other words, the patients in the PPS group had significantly earlier stage disease than their counterparts (i.e., patients with the same type of metastatic spine tumor) in the conventional group.
Of course, combining PPS with multidisciplinary adjuvant therapy might have significant beneficial effects on the postoperative survival time and/or the Barthel index. The increase in the survival time after posterior stabilization alone seen in the PPS group was of course due to recent developments in multidisciplinary treatment, and the frequency of the combined use of surgery and radiotherapy and/or chemotherapy (as adjuvant therapy) was significantly higher in the PPS group (P = 0.0027). However, the role of surgery in making adjuvant therapy possible is very significant; i.e., PPS surely contributed to the observed increase in the frequency of adjuvant therapy. Rao et al. pointed out that PPS might lead to an improvement in prognosis because it allows adjuvant therapy to be used to treat primary and metastatic lesions early after surgery.32 Kim et al. also observed a higher frequency of adjuvant therapy after surgery involving PPS.33 Fortunately, despite the number of patients being small in the present study, survival after posterior stabilization alone was significantly prolonged in the PPS group.
It was difficult to perform intergroup comparisons of the rates of improvement in paralysis and the Barthel index in the current study because differences in the preoperative severity of paralysis/the Barthel index were detected between the two groups. However, it is well known that the outcomes of treatment for metastatic spine tumors depend on the grade of paralysis and/or the patient's ability to perform ADL.34,35 Therefore, from the viewpoint of palliative treatment, it is important to start treatment as early as possible. If possible, it is desirable to ensure that the patient's ability to perform ADL is maintained at a high level and to prevent paralysis. Hence, in the current study, posterior stabilization involving PPS combined with multidisciplinary adjuvant therapy was demonstrated to produce superior functional results in patients with earlier stage metastatic spine tumors.
This study had several limitations. Although the severity of the subjects' systemic conditions was matched using the Tokuhashi score, this was a retrospective study, and the number of patients was small. Furthermore, because the subgroups were treated in different time periods, the types (severity) of symptoms that were indicated for surgery and the modality of the adjuvant treatment varied between them. A randomized controlled study involving a large number of patients might be necessary in the future.
Since the outcomes of palliative surgery for metastatic spine tumors are determined by the type of primary cancer and the era in which the surgery is performed because cancer treatment progresses, e.g., molecule-targeting drugs have recently been developed, careful evaluation of our findings is necessary.
Conclusions
Performing posterior decompression and stabilization with PPS did not result in a significant reduction in surgical stress, and the outcomes of such surgery were not significantly better than those achieved by conventional posterior decompression and stabilization. However, compared with conventional stabilization alone, combining PPS-based posterior stabilization alone with multidisciplinary adjuvant therapy expanded the age range of the subjects indicated for surgery and had significant beneficial effects on surgical stress, postoperative survival time, and Barthel index in patients with earlier stage metastatic spine tumors.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
References
- 1.Gilbert RW, Kim JH, Posner JB. Epidural spinal cord compression from metastatic tumor: Diagnosis and treatment. Ann Neurol. 1978;3:40–51. doi: 10.1002/ana.410030107. [DOI] [PubMed] [Google Scholar]
- 2.Patchell RA, Tibbs PA, Regine WF, Payne R, Saris S, Kryscio RJ, et al. Direct decompressive surgical resection in the treatment of spinal cord compression caused by metastatic cancer: A randomised trial. Lancet. 2005;366:643–8. doi: 10.1016/S0140-6736(05)66954-1. [DOI] [PubMed] [Google Scholar]
- 3.Chaichana KL, Woodworth GF, Sciubba DM, McGirt MJ, Witham TJ, Bydon A, et al. Predictors of ambulatory function after decompressive surgery for metastatic epidural spinal cord compression. Neurosurgery. 2008;62:683–92. doi: 10.1227/01.neu.0000317317.33365.15. [DOI] [PubMed] [Google Scholar]
- 4.Crnalic S, Hildingsson C, Bergh A, Widmark A, Svensson O, Löfvenberg R, et al. Early diagnosis and treatment is crucial for neurological recovery after surgery for metastatic spinal cord compression in prostate cancer. Acta Oncol. 2013;52:809–15. doi: 10.3109/0284186X.2012.705437. [DOI] [PubMed] [Google Scholar]
- 5.Quraishi NA, Rajagopal TS, Manoharan SR, Elsayed S, Edwards KL, Boszczyk BM, et al. Effect of timing of surgery on neurological outcome and survival in metastatic spinal cord compression. Eur Spine J. 2013;22:1383–8. doi: 10.1007/s00586-012-2635-y. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Cole JS, Patchell RA. Metastatic epidural spinal cord compression. Lancet Neurol. 2008;7:459–66. doi: 10.1016/S1474-4422(08)70089-9. [DOI] [PubMed] [Google Scholar]
- 7.Falicov A, Fisher CG, Sparkes J, Boyd MC, Wing PC, Dvorak MF, et al. Impact of surgical intervention on quality of life in patients with spinal metastases. Spine (Phila Pa 1976) 2006;31:2849–56. doi: 10.1097/01.brs.0000245838.37817.40. [DOI] [PubMed] [Google Scholar]
- 8.Jónsson B, Sjöström L, Olerud C, Andréasson I, Bring J, Rauschning W, et al. Outcome after limited posterior surgery for thoracic and lumbar spine metastases. Eur Spine J. 1996;5:36–44. doi: 10.1007/BF00307825. [DOI] [PubMed] [Google Scholar]
- 9.Weigel B, Maghsudi M, Neumann C, Kretschmer R, Müller FJ, Nerlich M, et al. Surgical management of symptomatic spinal metastases. Postoperative outcome and quality of life. Spine (Phila Pa 1976) 1999;24:2240–6. doi: 10.1097/00007632-199911010-00012. [DOI] [PubMed] [Google Scholar]
- 10.Pointillart V, Vital JM, Salmi R, Diallo A, Quan GM. Survival prognostic factors and clinical outcomes in patients with spinal metastases. J Cancer Res Clin Oncol. 2011;137:849–56. doi: 10.1007/s00432-010-0946-0. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Pascal-Moussellard H, Broc G, Pointillart V, Siméon F, Vital JM, Sénégas J, et al. Complications of vertebral metastasis surgery. Eur Spine J. 1998;7:438–44. doi: 10.1007/s005860050105. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Quan GM, Vital JM, Aurouer N, Obeid I, Palussière J, Diallo A, et al. Surgery improves pain, function and quality of life in patients with spinal metastases: A prospective study on 118 patients. Eur Spine J. 2011;20:1970–8. doi: 10.1007/s00586-011-1867-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Miscusi M, Polli FM, Forcato S, Ricciardi L, Frati A, Cimatti M, et al. Comparison of minimally invasive surgery with standard open surgery for vertebral thoracic metastases causing acute myelopathy in patients with short- or mid-term life expectancy: Surgical technique and early clinical results. J Neurosurg Spine. 2015;22:518–25. doi: 10.3171/2014.10.SPINE131201. [DOI] [PubMed] [Google Scholar]
- 14.Hansen-Algenstaedt N, Kwan MK, Algenstaedt P, Chiu CK, Viezens L, Chan TS, et al. Comparison between minimally invasive surgery and conventional open surgery for patients with spinal metastasis: A prospective propensity score-matched study. Spine (Phila Pa 1976) 2017;42:789–97. doi: 10.1097/BRS.0000000000001893. [DOI] [PubMed] [Google Scholar]
- 15.Gu Y, Dong J, Jiang X, Wang Y. Minimally invasive pedicle screws fixation and percutaneous vertebroplasty for the surgical treatment of thoracic metastatic tumors with neurologic compression. Spine (Phila Pa 1976) 2016;41(Suppl 19):B14–B22. doi: 10.1097/BRS.0000000000001811. [DOI] [PubMed] [Google Scholar]
- 16.Uei H, Tokuhashi Y, Oshima M, Maseda M, Matsumoto K, Soma H, et al. Clinical results of minimally invasive spine stabilization for spinal metastases. Orthopedics. 2017;40:e693–8. doi: 10.3928/01477447-20170522-02. [DOI] [PubMed] [Google Scholar]
- 17.Uei H, Tokuhashi Y, Maseda M, Nakahashi M, Sawada H, Nakayama E, et al. Clinical results of multidisciplinary therapy including palliative posterior spinal stabilization surgery and postoperative adjuvant therapy for metastatic spinal tumor. J Orthop Surg Res. 2018;13:30. doi: 10.1186/s13018-018-0735-z. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 18.Uei H, Tokuhashi Y, Maseda M, Nakahashi M, Sawada H, Nakayama E, et al. Comparison between minimally invasive spine stabilization with and without posterior decompression for the management of spinal metastases: A retrospective cohort study. J Orthop Surg Res. 2018;13:87. doi: 10.1186/s13018-018-0777-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 19.Tokuhashi Y, Matsuzaki H, Oda H, Oshima M, Ryu J. A revised scoring system for preoperative evaluation of metastatic spine tumor prognosis. Spine (Phila Pa 1976) 2005;30:2186–91. doi: 10.1097/01.brs.0000180401.06919.a5. [DOI] [PubMed] [Google Scholar]
- 20.Bilsky MH, Laufer I, Fourney DR, Groff M, Schmidt MH, Varga PP, et al. Reliability analysis of the epidural spinal cord compression scale. J Neurosurg Spine. 2010;13:324–8. doi: 10.3171/2010.3.SPINE09459. [DOI] [PubMed] [Google Scholar]
- 21.Tokuhashi Y, Kawano H, Ohsaka S, Matsuzaki H, Toriyama S. A scoring system for preoperative evaluation of the prognosis of metastatic spine tumor (a preliminary report) Nihon Seikeigeka Gakkai Zasshi. 1989;63:482–9. [PubMed] [Google Scholar]
- 22.Ohnhaus EE, Adler R. Methodological problems in the measurement of pain: A comparison between the verbal rating scale and the visual analogue scale. Pain. 1975;1:379–84. doi: 10.1016/0304-3959(75)90075-5. [DOI] [PubMed] [Google Scholar]
- 23.Hornblow AR, Kidson MA. The visual analogue scale for anxiety: A validation study. Aust N Z J Psychiatry 1976) 10:339–41. doi: 10.3109/00048677609159523. [DOI] [PubMed] [Google Scholar]
- 24.Prodinger B, O'Connor RJ, Stucki G, Tennant A. Establishing score equivalence of the functional independence measure motor scale and the barthel index, utilising the international classification of functioning, disability and health and Rasch measurement theory. J Rehabil Med. 2017;49:416–22. doi: 10.2340/16501977-2225. [DOI] [PubMed] [Google Scholar]
- 25.Frankel HL. Traumatic paraplegia. Nurs Mirror Midwives J. 1975;141:48–52. [PubMed] [Google Scholar]
- 26.Mahoney FI, Barthel DW. Functional evaluation: the barthel index. Md State Med J. 1965;14:61–5. [PubMed] [Google Scholar]
- 27.Jeanneret B, Magerl F. Treatment of osteomyelitis of the spine using percutaneous suction/irrigation and percutaneous external spinal fixation. J Spinal Disord. 1994;7:185–205. doi: 10.1097/00002517-199407030-00001. [DOI] [PubMed] [Google Scholar]
- 28.Foley KT, Gupta SK, Justis JR, Sherman MC. Percutaneous pedicle screw fixation of the lumbar spine. Neurosurg Focus. 2001;10:E10. doi: 10.3171/foc.2001.10.4.11. [DOI] [PubMed] [Google Scholar]
- 29.Klimo P, Jr, Kestle JR, Schmidt MH. Treatment of metastatic spinal epidural disease: A review of the literature. Neurosurg Focus. 2003;15:E1. doi: 10.3171/foc.2003.15.5.1. [DOI] [PubMed] [Google Scholar]
- 30.Tancioni F, Navarria P, Pessina F, Marcheselli S, Rognone E, Mancosu P, et al. Early surgical experience with minimally invasive percutaneous approach for patients with metastatic epidural spinal cord compression (MESCC) to poor prognoses. Ann Surg Oncol. 2012;19:294–300. doi: 10.1245/s10434-011-1894-x. [DOI] [PubMed] [Google Scholar]
- 31.Zairi F, Arikat A, Allaoui M, Marinho P, Assaker R. Minimally invasive decompression and stabilization for the management of thoracolumbar spine metastasis. J Neurosurg Spine. 2012;17:19–23. doi: 10.3171/2012.4.SPINE111108. [DOI] [PubMed] [Google Scholar]
- 32.Rao PJ, Thayaparan GK, Fairhall JM, Mobbs RJ. Minimally invasive percutaneous fixation techniques for metastatic spinal disease. Orthop Surg. 2014;6:187–95. doi: 10.1111/os.12114. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 33.Kim CH, Chung CK, Sohn S, Lee S, Park SB. Less invasive palliative surgery for spinal metastases. J Surg Oncol. 2013;108:499–503. doi: 10.1002/jso.23418. [DOI] [PubMed] [Google Scholar]
- 34.Tokuhashi Y, Ajiro Y, Umezawa N. Outcome of treatment for spinal metastases using scoring system for preoperative evaluation of prognosis. Spine (Phila Pa 1976) 2009;34:69–73. doi: 10.1097/BRS.0b013e3181913f19. [DOI] [PubMed] [Google Scholar]
- 35.Rades D, Hueppe M, Schild SE. A score to identify patients with metastatic spinal cord compression who may be candidates for best supportive care. Cancer. 2013;119:897–903. doi: 10.1002/cncr.27849. [DOI] [PubMed] [Google Scholar]