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      ORIGINAL ARTICLE Year : 2023  |  Volume : 71  |  Issue : 5  |  Page : 902-906

Measuring the Delay in the Referral of Unstable Vertebral Metastasis to the Spine Surgeon: A Retrospective Study in a Latin American Institution

Federico Landriel1, Fernando Padilla Lichtenberger1, Liezel Ulloque-Caamaño2, Candelaria Mosquera3, Martina Aineseder4, Jimena Maur Perotti5, Santiago Hem1
1 Neurosurgical Department, Spine Unit, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
2 Neurosurgical Department, Hospital Ángel C. Padilla, San Miguel de Tucumán, Tucumán, Argentina
3 Health Informatics Department, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
4 Radiology Department, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina
5 Oncology Department, Hospital Italiano de Buenos Aires, Buenos Aires, Argentina

Date of Submission16-Jul-2022Date of Decision10-May-2023Date of Acceptance23-May-2023Date of Web Publication18-Oct-2023

Correspondence Address:
Federico Landriel
Neurosurgical Department, Spine Unit, Hospital Italiano de Buenos Aires, Buenos Aires
Argentina

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/0028-3886.388118

Background: The delay in the referral of patients with potential surgical vertebral metastasis (VM) to the spine surgeon is strongly associated with a worse outcome. The spinal instability neoplastic score (SINS) allows for determining the risk of instability of a spine segment with VM; however, it is almost exclusively used by specialists or residents in neurosurgery or orthopedics. The objective of this work is to report the delay in surgical consultation of patients with potentially unstable and unstable VM (SINS >6) at our center.
Material: We performed a 5-year single-center retrospective analysis of patients with spine metastasis on computed tomography (CT). Patients were divided into Group 1 (G1), potentially unstable VM (SINS 7-12), and Group 2 (G2), unstable VM (SINS 13-18). Time to surgical referral was calculated as the number of days between the report of the VM in the CT and the first clinical assessment of a spinal surgeon on the medical records.
Results: We analyzed 220 CT scans, and 98 met the selection criteria. Group 1 had 85 patients (86.7%) and Group 2 had 13 (13.3%). We observed a mean time to referral of 83.5 days in the entire cohort (std = 127.6); 87.6 days (std = 135.1) for G1, and 57.2 days (std = 53.8) for G2. The delay in referral showed no significant correlation with the SINS score.
Conclusion: We report a mean delay of 83.5 days in the surgical referral of VM (SINS >6, n = 98). Both groups showed cases of serious referral delay, with 25% of patients having the first surgical consultation more than three months after the CT study.

Keywords: Oncological surgical delay, SINS referral delay, spine tumor referral delay, unstable metastasis surgical referral delay
Key Message: There is a serious delay in the surgical referral of potentially or unstable vertebral metastasis (VM)

How to cite this article:
Landriel F, Lichtenberger FP, Ulloque-Caamaño L, Mosquera C, Aineseder M, Perotti JM, Hem S. Measuring the Delay in the Referral of Unstable Vertebral Metastasis to the Spine Surgeon: A Retrospective Study in a Latin American Institution. Neurol India 2023;71:902-6
How to cite this URL:
Landriel F, Lichtenberger FP, Ulloque-Caamaño L, Mosquera C, Aineseder M, Perotti JM, Hem S. Measuring the Delay in the Referral of Unstable Vertebral Metastasis to the Spine Surgeon: A Retrospective Study in a Latin American Institution. Neurol India [serial online] 2023 [cited 2023 Oct 19];71:902-6. Available from: https://www.neurologyindia.com/text.asp?2023/71/5/902/388118

The delay in the referral of patients with potential surgical vertebral metastasis (VM) to the spine surgeon is strongly associated with a worse surgical and postoperative outcome.[1] Spinal cord compression and instability due to VM are independent indications for surgical treatment.[2] The former is easily detected as it causes significant symptoms and presents pathognomonic images on magnetic resonance imaging (MRI). In many centers, this finding is linked to red-flag protocols in which spinal surgeons are notified directly by the radiologists when the imaging study is completed. Spinal instability, on the other hand, is usually overlooked, as most practitioners are not familiar with its assessment. Consequently, spine surgeons who are familiar with the management of unstable spinal metastatic disease are often involved late in the decision-making treatment. The spinal instability neoplastic score (SINS) is an internationally validated scale that allows for determining the risk of instability of a spine segment with VM[3]; however, it is almost exclusively used by specialists or residents in spinal surgery, neurosurgery, or orthopedics.

The objective of this work is to study the referral pattern and delay in surgical consultation of patients with potentially unstable and unstable VM (SINS >6). These initial findings could encourage both the implementation of training programs on SINS calculation for radiologists and oncologists as well as the development of automated tools for image analysis, as strategies to improve referral times of unstable VM and thus patient outcomes.

  Material and Methods 

Data collection

This study received institutional review board approval (IRB 5833 October 2021). Informed consent is not required. We performed a single-center retrospective analysis of patients with a radiological report of VM, spine secondaries, or infiltration on a spinal computed tomography (CT) scan from January 1, 2015, to December 31, 2020, with known or unknown primary tumors. We analyzed the clinical records of patients to retrieve age, sex, clinical signs, and histopathological results, which were systematically recorded in the hospital medical database. CT images were obtained from the hospital imaging database.

We excluded CT studies performed after spinal surgical treatment, with osteoporotic/traumatic fractures, or poor radiological technique (incomplete study, artifacts caused by movement or osteosynthesis, or superimposed external elements). We excluded patients in whom the CT scan was requested by the spinal surgeon in search of spinal metastases and patients with a prior diagnosis of VM.

A group of neurosurgeons evaluated independently the SINS scale of metastasis in the CT scans, combined with X-rays and MRI. Medical records were studied to determine the presence of pain exacerbated by movement and relieved by rest in the spine-affected region.

The SINS evaluates a score from the six following factors: spinal location of the tumor, pain, bone lesion quality, spinal alignment, vertebral body collapse, and posterior elements involvement. Scores of 0 to 6 denote “stability,” scores of 7 to 12 denote “indeterminate instability,” and scores of 13 to 18 denote “instability.”[3]

Patients were divided into two groups: Group 1 (G1), patients with potentially unstable VM (SINS score between 7 and 12 points), and Group 2 (G2), patients with unstable VM (SINS score from 13 to 18 points). Patients with SINS <7 were excluded.

Statistical analysis

The main outcome of this study was the time to surgical referral, calculated as the number of days that elapsed between the report of the VM in the CT scan and the first clinical note of a spinal surgeon in the medical records of the patient. We studied the distribution of delay for the entire cohort and for both groups separately. The difference in delay between the two groups was contrasted using a parametric Student's t-test of the normalized distribution. The effect of SINS on the time to referral was evaluated using a generalized linear regression model. The effect of sex, age, and year of CT was also evaluated. For all tests, the level of statistical significance was established at 0.05. The statistical analysis was performed with the Statistical Package for the Social Sciences (SPSS) 20.0 (IBM Corp., Armonk, NY, USA) software.

  Results 

We analyzed 220 CT scans, of which 98 met the selection criteria (48 women and 50 men). G1 had 85 patients (86.7%) and G2 had 13 (13.3%). The mean age at diagnosis was 63.2 years for the entire cohort (std = 14.6); 64 years (std = 14.6) for G1 and 60 years (std = 14.7) for G2. The most frequent primary neoplasms' locations were breast (n = 21), kidney (n = 20), and lung (n = 17).

We observed a mean time to referral of 83.5 days in the entire cohort (std = 127.6); 87.6 days (std = 135.1) for G1, and 57.2 days (std = 53.8) for G2. Box plots are presented in [Figure 1]. Four patients in G1 showed a delay in surgical consultation of more than one year after the CT study.

Figure 1: Distribution of time to referral (delay) for G1 (potentially unstable VM) and G2 (unstable VM), expressed in days

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The outcome variable did not show a normal distribution (Kolmogorov–Smirnov normality test P < 0,05), so the median and interquartile ranges were evaluated to compare delay in both groups. [Table 1] reports descriptive statistics. For unstable VM, we observe that although the mean delay is a month shorter than for potentially unstable cases, the median is greater. This is attributed to the small sample size of G2.

Table 1: Descriptive statistics of the time to surgical referral, expressed in days

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To study the difference in the time to referral between the two groups, we used the logarithmic transformation of the variable, which showed a normal distribution (Kolmogorov–Smirnov normality test P = 0,75). The difference in the meantime to referral between the two groups was non-significant (Student's t-test P = 0.98). This suggests that surgical referral should be improved both for unstable and potentially unstable cases. We illustrate a patient's case in [Figure 2], as an example of the surgical referral process in a 39-year-old patient with clear cell kidney carcinoma and thoracic back pain.

Figure 2: Represents an example of the surgical referral delay in a 39-year-old patient with clear cell kidney carcinoma and thoracic back pain. A, B, and C images demonstrate an 8-month delay in surgical consultation for a potentially unstable T6 metastasis. (a) Sagittal computed tomography (CT) image of a T6 metastasis, SINS 8. (b) 150-day CT control after radiotherapy, the patient still had mechanical pain. (c) CT image control post-T6 augmentation. The patient had pain relief after this treatment and 240 days. D, E, and F show red-flag workflow in spinal cord compression syndrome in the same patient. (d) CT 3 months after T6 augmentation, the yellow arrow shows a new C7 unstable metastasis - SINS 13. The patient was referred for cervicalgia and lower limbs paresthesia. (e) T2-WI sagittal magnetic resonance imaging shows yellow arrows in C5 and C7 unstable metastases with spinal cord compression and myelomalacia. (f) CT postoperative control, a yellow arrow mark cervical decompression, and stabilization. The patient improved his symptoms in less than a week

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We evaluated the correlation between SINS and time to referral and observed a descending trend in delay as SINS increases, as illustrated in [Figure 3]. This is expected, as VMs with higher SINS are severe and easier to identify as potential surgical cases. However, this correlation was not significant (Pearson correlation = 0.15). The effect of the SINS as a continuous variable in the time to referral was further studied with a generalized linear regression model, showing also a non-significant effect. The effect of sex, age, and year of CT study was also evaluated with the generalized linear regression model, with no variable showing a significant effect [see [Table 2]].

Figure 3: Scatter plot of SINS and time to referral (delay). The descending trend is shown as a dotted line

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  Discussion 

The clinical diagnostic path of VM differs greatly between spinal compression cases and instability cases. Nowadays, it is rare for a spinal cord or nerve root compression to be overlooked, as neurological deficits are a widely recognized symptom. This finding is widely recognized as a medical emergency, and most centers have red-flag notification protocols at the time of imaging diagnosis to alert the spinal surgeon, even in asymptomatic patients. In a cohort of 301 consecutive patients with malignant spinal tumors conducted more than 20 years ago, Husband et al. reported a median delay of 14 days from the onset of symptoms of spinal cord compression to treatment. Of the total delay, three days were accounted for by patients, three days by general practitioners, four days by the district general hospital, and no days by the treatment unit.[4]

Spine instability in the context of a VM is defined as the loss of spinal integrity as a result of a neoplastic process that is associated with movement-related pain, symptomatic of progressive deformity, and/or neural compromise under physiological loads.[3] The treatment delay in these fragile patients has direct and indirect adverse consequences for functional performance status, quality of life, and survival.[1],[5] However, the symptoms of unstable VM are easily overlooked: most patients experience back pain, nocturnal back pain, progressive back pain, or pain on palpation. These symptoms could be dismissed in medical consultations, as back pain is a non-specific and widely spread condition in the current sedentary population, which is sometimes chronic and usually not associated with a VM.[6] Even patients and their families—who usually become masters of their own disease—may not identify these symptoms due to a lack of knowledge.[7],[8]

Husband et al.[4] described a median total delay from the onset of back pain until the surgical treatment of 73.5 days in patients with a history of malignancy and 90 days in patients without a cancer history. Levack et al.[8] also found a total median delay of 90 days. Dosani et al.[9] reported that only 5.6% of the patients in their cohort were referred to a spinal surgeon before palliative radiation. Of these, one out of 66 patients with SINS <7 was referred for surgical consultation (1.5%), 7 out of 115 patients with SINS between 7 and 12 (6.1%), and 3 out of 14 patients with SINS >13 (21.4%). The median time to referral from the date of radiation to the spine surgeon consultation was four months (120 days), ranging between 0.1 and 6.8 months. They estimated that if all patients with potentially unstable or unstable VM had been referred to a spine surgeon, the number of spinal assessments would have increased 11-fold.

Hospital multidisciplinary tumor boards have an advantage in the management of VM by avoiding poor outcomes in surgical emergencies.[10] The establishment of these institutional boards reduces the number of known cancers' VM operated in emergencies.[11] The participation of physicians from different specialties in these regular meetings has improved education and therapeutic planning. However, if such meetings take place without a spine surgeon present, proper treatment of spine instability might be delayed, as its detection is more demanding for non-surgical members of the multidisciplinary care team than the detection of spinal cord compression, which is more widespread.[5]

Although the education of other specialists on the detection of spinal instability could be an alternative, Galasko et al.[12] pointed out more than 20 years ago the difficulty of surgeons to educate their colleagues from other specialties on the management of unstable VMs. The SINS score has been shown to accurately guide treatment, yielding consistency across and within reviewers of many non-surgical spine specialties, and it is currently applied worldwide.[6],[13],[14] SINS can be summarized in a binary scale: stable (0-6 points) and currently or possibly unstable (7-18 points), with surgical consultation recommended in the latter.[6] As Goodwin et al.[15] state, “the greatest impact of this scoring system will come from non-spinal surgeons who will use this system to determine which patient is in need of referral to a spinal surgeon.” However, according to previous works, only 14% of clinicians in oncology care are familiar with the available scoring systems,[16] and more than 70% of patients with cancer have pathological evidence of VM at the time of death.[17]

This problem is further evidenced in the delay times reported in the prior works mentioned above. The purpose of this study was to measure the delay at our institution, as no prior work reported time to referral in a health institution in a developing country. Our findings confirm that we still face problems in the daily routine when it comes to spinal instability diagnosis, even when hospital tumor boards take place.

The purpose of this work was to measure a problem in our institutional clinical workflow. The results of this study represent reliable institutional data on the surgical referral delay of unstable VM, which can be used as a baseline to measure the impact of new implementations in our center. These could include educational activities for physicians or patient training programs to recognize the SINS score and the implementation of red-flag protocols for unstable VM in CT reports. For future work, we are currently developing an automated tool for image analysis based on artificial intelligence, which can assist non-spinal specialists in recognizing unstable VM, designed as a clinical decision support system.

Limitations

The main limitation is that the study was performed at a single center, so its results might not be generalized. Another limitation was that the method to determine the referral date for potentially or unstable VM might overlook off-the-record consultations. Referral might occur by phone or in-person conversation between the physician and the spinal surgeon. We chose two time-points that can be retrieved from the patient's health record, measuring the referral time as the lapse between the radiological report of the CT scan and the first written medical note of the spine surgeon. This aspect compromises the direct comparison with values reported in prior works. Moreover, low back pain or related symptoms might not be recorded in the patient's health record, affecting the calculation of the true SINS value.

  Conclusion 

We report an institutional mean delay of 83.5 days in the surgical referral of VM (SINS >6, n = 98). Although we observed a smaller mean delay for unstable VM than for potentially unstable VM, both groups showed cases of serious referral delay, with 25% of patients having the first surgical consultation more than three months after the CT study.

Acknowledgements

This study was organized by the AO Spine Latin America Tumor Study Group. AO Spine is a clinical division of the AO Foundation, which is an independent medically guided not-for-profit organization.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 

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  [Table 1], [Table 2]