<b>SURGICAL INTERVENTION -- VERTEBRAL METASTASES</b>

<b>The spine is the commonest site for skeletal metastases. </b> Sometimes the vertebrae are invaded by direct extension of a nearby tumor in the lung, neck, or abdomen.  Sometimes the metastases arrive at the vertebrae by means of blood-borne spread, from the primary, through the lung circulation, to the peripheral circulation.  The tumor might possibly also spread to the vertebrae via a "third circulation", the Batson plexus, a network of deep pelvic veins with rich anastomoses [connections] to the vertebral plexus [another network of veins].  [1, 2]  

Metastatic tumors destroy vertebrae so that they spontaneously fracture [called a "pathologic" fracture].  If the vertebral pieces move out of alignment, they can cause major damage to the spinal cord, resulting in paralysis of the lower body [paraplegia] or all four limbs [quadriplegia], depending upon where the fracture is.  Metastases in the spine can also cause symptoms from tumors growing into the spinal canal and pressing upon the spinal cord.   Due to advances in spinal surgery, effective help often can be provided to these patients. The extent and type of surgical intervention, however, must be carefully considered in each individual case.  [3, 4] 

"The development of back pain in a patient with cancer, associated with an abnormality on a plain spinal radiograph, should serve as a warning for the possible development of spinal cord compression. In this situation more than 60% of patients will have myelographic abnormalities or evidence of epidural disease on magnetic resonance imaging. The key to successful rehabilitation is early diagnosis, high-dose corticosteroids, rapid assessment, and urgent referral for both decompression and spinal stabilization or radiotherapy. Neurological recovery is unlikely if the spinal compression is not relieved within 24-48 h."  [5] 
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<b>"Spinal instability is a cause of back pain in approximately 10% of patients with metastatic bone disease. This can cause excruciating pain, which is mechanical in origin. The patient is only comfortable when lying absolutely still and any movement reproduces severe pain. </b>Consequently, the patient may not be able to sit, stand or walk even with the use of a spinal support. <b>Because the pain is due to the instability, radiotherapy or systemic treatment will not relieve the pain</b>. As with a pathological long-bone fracture, stabilization is required for pain relief. This involves major surgery, which may be associated with significant morbidity and mortality.<b> There are several methods of spinal stabilization, but the posterior approach is technically easier and allows stabilization of a longer length of the spine. With careful selection of patients, excellent results can be obtained [6] </b>

Criteria for impending vertebral collapse have been described as:  "50-60% involvement of the vertebral body with no destruction of other structures, or 25-30% involvement with costovertebral joint destruction in the thoracic spine; and 35-40% involvement of vertebral body, or 20-25% involvement with posterior elements destruction in thoracolumbar and lumbar spine. ...  With respect to the timing and occurrence of vertebral collapse, there is a distinct discrepancy between the thoracic and thoracolumbar or lumbar spine. When a prophylactic treatment is required, the optimum timing and method of treatment should be selected according to the level and extent of the metastatic vertebral involvement. "[7]

<b>Surgical intervention is the treatment of choice for unstable vertebrae or neurologic deficit, with the excision of the tumorous bone and stabilization of the spine. </b> "Coincident with improved overall cancer palliation during the past 2 decades has been an increasing incidence of clinically apparent bone metastases, and from these metastases subsequent pathologic fractures of the long bones, spine, and pelvis. Current techniques for surgical management of these fractures are extremely effective in alleviating pain and allowing patients to resume an ambulatory status, often without the need of external support. This, in turn, has significantly improved the quality of the remaining months or years of these individuals' lives. In fact, the long term survival of patients after their first long bone pathologic fracture from malignancy has more than tripled for the most common cancers (breast carcinoma, prostate carcinoma, lymphomas, and myelomas) during the past 25 years."  [87]

Generally, surgery is recommended, with tumor excision, and removal of tumorous parts or the entire vertebra.  It is recommended that surgery be done BEFORE there is major neurological deficit, as the results are much better.   "Surgical indications must be made at the first sign of deficit, regardless of the degree of compression present in the radiologic documentation, in order to avoid the transformation of reversible functional medullary changes into irreversible structural lesions."   [78]

Results of surgical excision of metastatic neoplastic disease and stabilization of the spine seem to be overwhelmingly positive.  Surgical intervention does prevent paraplegia, quadriplegia, and other neurologic deficit, as well as managing pain.  The surgical techniques are well developed, and hospitalizations are not long, but complications can occur, and hemorrhage is one of them.    Techniques vary, and can vary also with site of the tumor.  
Excisions dealing with LMS lesions should always be en bloc if it is at all possible.  That means that the tumor and its environs are removed in one resected piece, with wide margins.  There is no cutting into the tumor, or removing the tumor piecemeal.  [21, 30, 80, 111, 139]
"Embolization of vertebral metastases is a safe treatment prior to surgical resection. With appropriate monitoring, complications can be eliminated. The resulting devascularization allows for an aggressive resection of pathologic tissue."  As well as decreasing hemorrhagic complications.  [126]

"The spine is the commonest site for skeletal metastases. <b>The majority of patients with spinal metastases can be managed conservatively, at least initially, but a significant number will develop complications, either neurological or mechanical, requiring surgical intervention. This paper emphasizes the need for a spinal surgeon to be involved early in the care of these patients...</b>Post-operatively pain improved in 38 of the 42 patients (90%), the neurological deficit in 20 of the 29 patients with a deficit (69%) and the ambulatory ability in 25 of the 32 patients (78%) with very restricted mobility...: Identification of the cause of a patient's symptoms allows appropriate surgical intervention with favorable results." [36]

"Most spinal metastases can be managed conservatively. Those requiring surgical intervention present with progressive neurologic compromise, which requires decompression, or spinal instability, which requires stabilization. Constructs for internal stabilization of the spine must not be adversely affected by local postoperative irradiation. ... Eighty-two percent of patients with neurologic compromise secondary to vertebral malignancy improve at least one functional grade after decompression and stabilization, and 88% experience good or excellent relief of spinal pain with restoration of walking ability. Thirty-two percent survived for more than 2 years after spinal decompression and stabilization. Patients with pathologic fractures from metastatic carcinoma of the breast had a mean survival of 24.6 months after surgical management of their fractures. There was a similarly encouraging improvement in the survival statistics for patients with other primary tumor types. Most malignant pathologic fractures of the pelvis, long bones, or spine are amenable to effective stabilization by the techniques described in this article. These techniques allow resumption of weight-bearing ambulation in all but a few patients, good or excellent relief of pain in the vast majority, and an enhanced anticipation of survival and improvement in quality of life "[87]

Twenty-one patients between 39-71 years underwent reconstructive surgery for destructive spinal tumors. Tissue was removed with autogenous bone grafting with or without vertebral prosthesis resulting in early ambulation,  relief of pain, and neurological recovery reported in all.  There were no complications from surgery.  Surgical intervention is recommended where "reasonable longevity" is expected.  [17]

Surgical Complications:  In one study "90 patients underwent minimally invasive spinal surgery by thoracoscopic assistance as treatment for their anterior spinal lesions. A total of 30 complications were noted in 22 patients (24.4%). Two fatal complications occurred, resulting from massive blood transfusion in one case and postoperative pneumonia in another. Other nonfatal complications included four cases of transient intercostal neuralgia, three superficial wound infections, three cases of pharyngeal pain, two cases of lung atelectasis, two cases of residual pneumothorax, two cases of subcutaneous emphysema, one inadvertent pericardial penetration due to adhesion, one chylothorax that resolved after conservative management, one vertebral screw malposition, and one graft dislodgement that needed late revision surgery. Three patients required ventilatory support for longer than 72 hours. Five patients with spinal metastases had an estimated intraoperative blood loss of more than 2,000 ml. No injury to the internal organs or spinal cord was observed. There were four conversions to open procedures due to two cases of severe pleural adhesions and two poorly tolerated one-lung ventilation. At the latest follow-up, nine patients had died as a result of cancer dissemination. CONCLUSIONS: (a) Well-selected patients and attention to details are essential to optimizing surgical results. (b) A refined technique for less invasive tumor surgery has been developed. (c) Surgeons had better experience with the standard anterior spinal approach and showed no hesitation in converting to an open procedure when necessary. A procedure failure does not mean a treatment failure." [60] 

Children with vertebral metastases who are treated with chemo, radiation and laminectomy, and who survive longer than 2 months, will probably develop spinal deformity if spinal stabilization is not carried out. [155 ]

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