We retrospectively reviewed the data of 27 consecutive patients with neoplastic spinal compression who were treated with MISt and received immediate rehabilitation thereafter. Before the surgery, the status of impairment was evaluated based on both spine-specific factors and other factors. The neurological deficit, ambulation status, progress of pathological fracture, collapse, and postoperative implant failure were examined. Furthermore, the relationship between the improvement of Barthel index (BI)  and prognosis was statistically analyzed.
This retrospective study was conducted at Nara Medical University Hospital. The study protocol was approved by the institutional review board of the hospital and was conducted in concordance with principles of the Declaration of Helsinki and with the laws and regulations of Japan. A consecutive cohort of 27 patients with neoplastic spinal cord compression from 2014 to 2017 who met the surgical indications described below were enrolled. The treatment strategy for all the patients was assessed by the multidisciplinary tumor board of our hospital. Informed consent was obtained through our website. Inclusion criterion was patients with MISt for neoplastic spinal cord compression during the study period. We provided informed consent to all patients and no cases opted-out. No cases were excluded from the study. Follow-up periods averaged at 420±357 days (range: 30-1305 days).
Surgical indication for MISt
Surgical indication for MISt was assessed comprehensively by the multidisciplinary tumor board for skeletal metastasis, based on clinical findings including (1) spinal instability, (2) radiological spinal compression, (3) prognosis, (4) feasibility for the stabilization surgery (whether patients had multiple spinal lesions), (5) presence of pain or neurological deficits. Spinal instability was evaluated using the spinal instability neoplastic scale (SINS) score . The SINS is generated by tallying each score from the 6 individual components (location, pain, bone lesion quality, spinal alignment, vertebral body collapse, and posterolateral involvement of spinal elements). It has excellent inter- and intraobserver reliability in determining three clinically relevant categories of stability . Score ≥ 7 was classified as potentially unstable or unstable. To assess the degree of cord compression, the 6-point epidural spinal cord compression (ESCC) grading scale was used . It is a magnetic resonance (MR) imaging-based grading scale, which is based on the degree of impingement of cerebrospinal fluid (CSF) space. The inter- and intraobserver reliability was reported from good to excellent . After grading, neurological findings were evaluated. Regarding prognosis, we referred to the Revised Tokuhashi score  and the new Katagiri score . Patients’ with estimated life expectancy of ≥ 1 month were assessed for surgery. The surgery involved a short posterior fixation with PPS placed at two vertebral levels above and two level below the lesion. Patients with multiple spinal lesions expanding the vertebra of planned fixation level were deemed unfeasible for surgery. In addition to fixation, posterior decompression was performed in cases of tumors occupying only the posterior epidural space and were not considered hemorrhagic by radiological and pathological findings.
Multidisciplinary tumor board for skeletal metastasis
The multidisciplinary tumor board (MDTB) for skeletal metastasis at Nara Medical University Hospital was established in 2010. Since then, the disability/impairment statuses of each patient have been evaluated. The treatment plans for approximately 100 patients have been discussed per year. The monthly board meetings are attended by physicians, medical oncologists, radiation oncologists, diagnostic radiologists, physiatrists, orthopedic oncologists, spine surgeons, advanced practitioners, oncological nurses, and clinical support staffs. Besides the regular monthly board meetings, web discussions are held for emergency cases selected based on the electronic medical record system of the hospital. Cases eligible for presentation include new or existing outpatients or inpatients with skeletal metastasis. The multidisciplinary tumor board supported coordination, communication, and decision making between team members. Based on these discussions at the board, all patients would immediately receive intensive and regular adjuvant treatments including radiation therapy, chemotherapy, palliative care, and rehabilitation.
Rehabilitation was started one day after surgery, and involved tasks like sitting, standing, and walking, similar to rehabilitation programs after general (non-oncological) spine surgeries. Four patients, who had complete motor paraplegia before the surgery, did not show any improvement in physical function, yet the stabilized spine enabled them to train in wheelchair riding with decreased pain.
All patients were hospitalized for surgery. Preoperative measurement was performed at admission, and post-operative measurement was performed at discharge, by medical doctors in the department of rehabilitation medicine. Primary outcome was the Barthel index. Secondary outcomes were neurological deficits using the Frankel Scale (A-E) , duration to the start of ambulation exercises, the progress of pathological fractures, incidence of vertebral collapse, post-operative implant failure, and overall survival.
The Frankel Scale
The Frankel Scale classifies the extent of the neurological/functional deficit into five grades. Frankel grade A patients are those with complete motor and sensory lesions. Grade B patients have sensory only functions below the level of injury. Grade C patients have some degree of motor and sensory function, but their retained/recovered motor function is useless. Grade D patients have useful, but abnormal, motor function below the level of injury. And grade E patients have complete motor/sensory recovery .
Duration to the start of ambulation exercises
Duration (days) to the start of ambulation exercise after the surgery was determined from the medical records.
Progress of pathological fractures and incidence of vertebral collapse
The progress of pathological fracture, vertebral collapse, or implant failure were checked using routine radiographs after surgery, which were taken every 3-4 weeks.
Overall survival was assessed at the final follow-up in the outpatient department. Patients were evaluated as alive with disease (AWD) or dead of disease (DOD). We found no patients with no evidence of disease (NED) or continuously disease free (CDF).
The Barthel index
The Barthel index (BI) is one of the most widely used rating scales for the measurement of activity limitations in patients with neuromuscular and musculoskeletal conditions . It consists of 10 items that measure a person’s daily functioning, including feeding, bathing, grooming, dressing, toilet uses, transfers, mobility, and stair use . BI received high mark reliability and validity ratings in various reports [27-29].
Statistical analysis was performed using the JMP14.0 software (SAS Institute, Cary, NC, USA) and G*Power software 3.1(University of Dusseldorf). A p-value of < 0.05 was considered statistically significant. The Wilcoxon signed-rank test was used to evaluate differences in the BI scores before and after surgery because the data was nonparametric using the Shapiro–Wilk test. The Mann-Whitney U test, Kruskal-Wallis test, and Spearman correlation test were used to evaluate the association between BI score gain and the variables including tumor progression, ESCC grade (1, 2 versus 3), SINs, and radiation therapy status.