Decompression or Stabilization
The spine is the most common, and most clinically challenging, site of bony metastasis (Abel et al. 2008). Individual functional status and overall disease prognosis vary considerably, and this leads to significant heterogeneity in the management of the spinal metastasis. In many individuals with symptomatic compression of the spinal cord, the cancer has progressed to a point where surgical intervention is not considered curative. Rather, the rationale for surgery and (neo)adjuvant chemotherapy or radiation is to relieve pain and to prevent or reverse neurologic deficits.
Attempts to decompress the spinal cord or stabilize the spine may employ an anterior, posterior or combined approach. Specifically, the mechanical instability and extent of cord compression caused by the lesion will affect the surgical strategy. While many studies have compared the outcomes of such procedures, unfortunately, most groups include individuals with variable pre-operative neurological deficits and do not provide enough details regarding neurological outcomes. However, as summarized in Table 9, several studies have aimed to determine the possible advantages of different surgical approaches.
|Abel et al. (2008)
|Population: Mean age: 60.0 yr; Gender: males=28, females=6; Injury etiology: carcinoma=20, plasmocytoma=5, other=9; Level of injury range: C8-L1.
Intervention: Participants underwent a posterior decompression and stabilization procedure. Decompression occurred via posterior and posterolateral removal of the compressed intraspinal tumor tissue. Stabilization was achieved with a screw-rod construct above and below the lesion. Standard therapy was provided as needed following the procedure. Outcomes were assessed pre-and postoperatively.
Outcome Measures: American spinal injury association (ASIA), Functional independence measure (FIM), Pain medication use, Complications.
|1. Three participants died post-admission due to complications from the tumor. Post-surgical complications included: deep vein thrombosis (n=2), lung embolism (n=1), gastrointestinal bleeding (n=1), pneumonia associated with lung atelectasis (n=1), and a deep wound infection (n=1).
2. There were no significant differences in ASIA scores from admission to post-surgery on light touch (p=0.07), sensation of pinprick (p>0.05), or motor function (p>0.70).
3. FIM scores significantly improved following surgery compared to admission (p<0.01).
4. Pain medications and dosing were either reduced (n=20), maintained (n=6) or not necessary (n=2). Three participants required more potent pain medications.
|Chong et al. (2012)
|Population: Mean age: 58.3 yr; Gender: male=72, female=33; Level of injury: single thoracic=29, multiple thoracic=76; Severity of injury: Frankel A=1, B=1, C=21, D=40, E=42; Time since injury: not reported.
Intervention: Retrospective analysis of cases of non-traumatic SCI, resulting from vertebral metastasis, with onset between 2002-2010 in an institutional database. Outcomes were assessed two wk. following surgery, with follow-up for survival analysis.
Outcome Measures: Postoperative pain, Neurological improvement (Frankel score), ambulatory function.
|1. Postoperative pain improvement was observed in patients receiving anterior column reconstruction (p=0.02) or four of more levels of fixation (p<0.01).
2. Improvement in Frankel grade was observed in 20% of patients. Out of 21 Frankel C patients, 10 became ambulatory.
3. Preoperative Karnofsky Performance Scale (>70) and ambulatory status were significant predictors for postoperative ambulatory function.
4. The median overall survival of the patients was 6 mo.
5. Patient’s age (younger than 60), type of primary cancer (moderate and slow growth), no visceral metastases, less than three levels of spinal metastases and preoperative adjuvant therapy were positively significant for the patients’ survival (p<0.05).
6. Less than three levels of spinal metastases and postoperative adjuvant therapy were positively significant for the patient’s survival (hazard ratios of 0.53 and 0.48, p<0.05).
7. Patients with better functional outcomes showed increased chance of receiving postoperative adjuvant therapy (p<0.01).
|Rompe et al. (1999)
|Population: Mean age: 54 yr (men), 61 yr (women); Gender: male=54, female=52; Level of injury: cervical=26, thoracic=145, lumbar=88; Severity of injury: Frankel A=8, B=4, C=21, D=23, E=50; Time since injury: 2.8 yr.
Intervention: Prospective analysis of cases of non-traumatic SCI, resulting from vertebral metastasis with onset between 1987-1996. Outcomes were assessed one mo. following surgery, with follow-ups at 3 mo. intervals.
Outcome Measures: Neurological function (Frankel scale), perioperative complications, survival and rehabilitation.
Chronicity: The average length of stay in hospital was 29 days (range 15-46 days).
|1. Of 56 patients who had neurological deficits preoperatively, 35 experienced complete or partial recovery within the first 3 mo after the operation.
2. Of 50 patients without neurological dysfunction, 3 developed incomplete transient paresis.
3. A number of complications arose, including: pulmonary infections (n=9), deep vein obliterations (n=5), stress ulcer bleeding (n=2), deep wound infection (n=3), haematoma (n=1).
4. The rate of survival was 72% at 6 mo and 50% at 12 mo. At 12 mo, 42 of the 53 patients who were alive were able to walk.
5. Overall survival time was 19.2 mo, with 5 patients still alive.
6. Six patients required re-operation for tumour recurrence.
7. All patients who were able to walk were sent home. Thirteen patients were unable to walk and were discharged to nursing facilities.
|Gokaslan et al. (1998)
|Population: Median age: 56 yr; Gender: male=48, female=24; Level of injury: not reported; Severity of injury: not reported; Time since injury: not reported.
Intervention: No intervention. A retrospective review of patients who received metastatic spinal tumour resection surgery to determine outcomes.
Outcome measures: Surgical data (intraoperative blood loss, postoperative complications, number of days chest tubes were required, length of stay (LOS)), postoperative pain (Visual Analogue Scale – Pain), neurological status (Frankel scale), narcotic analgesic use, survival rate.
Chronicity: The median chest tube requirement was 4 days (range 1-26 days). The length of hospital stay ranged from 4 to 55 days (median 10 days).
|1. Total blood loss ranged from 100ml to 31L (median 850ml). Patients with renal cell disease showed more than a twofold increase in blood loss (median 1750ml; range 300-15 500ml).
2. Surgically related complications occurred in 21 patients (14 major and 10 minor). Major complications included epidural hematoma (n=3), pneumonia (n=3), gastrointestinal bleeding (n=2), cerebrospinal fluid leak (n=2), renal failure (n=2), cecal perforation (n=1) and pulmonary embolism (n=1).
3. The 30-day mortality rate was 3%. The overall 1 yr survival rate was 62%.
4. Of the 65 patients who presented with pain, complete resolution of pain was achieved in 23%. Pain was significantly improved in 69% and unchanged or worsened in 8%. Therefore, 92% of patients showed completely or greatly reduced pain postoperatively (p<0.001).
5. Analgesic pain medication usage was significantly reduced postoperatively (p<0.001).
6. Of the patients that presented with neurological dysfunction, 76% of patients improved neurologically after surgery (p<0.001), with 27 patients improving at least one Frankel grade and 20 patients regaining normal neurological function.
Bony metastasis in the spine is most commonly encountered in individuals with multiple myeloma, breast or prostate cancer. These lesions may lead to pathologic fractures and usually cause significant pain. Moreover, compression of the spinal cord and the resultant neurologic deterioration is a challenging complication. These findings represent disease progression and usually herald poor survival prognosis.
Numerous groups have proposed treatment strategies and reported the efficacy of surgical and adjuvant therapies (Abel et al. 2008; Chong et al. 2012; Gokaslan et al. 1998; Rompe et al. 1999). Treatment is aimed at preventing further neurologic deficits and for pain control. Surgical options include anterior, posterior or combined approaches for decompression and/or stabilization.
Above, we have summarized several well-designed studies which report surgical outcomes for individuals with metastatic spine lesions. As metastatic lesions most commonly arise within the vertebral body, anterior procedures or combined approaches are usually preferred for decompression. Gokaslan et al. (1998) reported the outcomes for 72 individuals with metastatic lesions who underwent trans-thoracic vertebrectomy. In this series, significant improvements in neurologic status and functionality were noted in 76% of individuals and pain was decreased in 92% of individuals.
While anterior procedures usually allow greater decompression, some individuals may not tolerate the procedure and others may also need posterior stabilization. Abel et al. (2008) report significant improvements in individual pain after posterior decompression and stabilization. They prevented progressive neurologic decline in 87% of individuals and functional status improved significantly in their individuals.
Given the heterogeneity in individual status, lesion characteristics and variations in surgical experience it is likely futile to argue for the superiority of a certain approach for decompression or stabilization for compression by metastatic lesions. Instead, the surgical technique should be individualized to achieve the objectives safely.