Satoru Demura

Total en bloc spondylectomy for spinal tumors: improvement of the technique and its associated basic background

Conventionally, curettage or piecemeal excision of vertebral tumors has been commonly practiced. However, clear disadvantages of these approaches include a high risk of tumor cell contamination of the surrounding structures and residual tumor tissue at the site due to the difficulty of distinguishing tumor from healthy tissue. These factors contribute to incomplete resection of the tumor as well as high local recurrence rates of spinal malignant tumors.1–3 Roy-Camille et al.,4,5 Stener,6–8 Stener and Johnsen,9 Sundaresan et al.,10 and Boriani et al.11,12 have described total corpectomy or spondylectomy for reducing local recurrence of a vertebral tumor, with excellent clinical results. Our own group has developed a new surgical technique of spondylectomy (vertebrectomy) termed total en bloc spondylectomy (TES).2,3,13–16 Our technique is different from the spondylectomy mentioned above in that it involves en bloc removal of the lesion, that is, removal of the whole vertebra, both body and lamina as one compartment. The TES procedure has been increasingly gaining recognition and is now widely accepted by spinal and musculoskeletal tumor surgeons a decade and a half after its development in 1989. This surgery is regarded as one of the most sophisticated and demanding operations; it requires a high level of technical ability and adequate knowledge and consideration of surgical anatomy, physiology, and biomechanics of both the spine and spinal cord. This level of understanding is not limited to oncological surgery but should be applied when surgically managing conditions of the spine and the spinal cord. The surgical skill of spine surgeons improves during the process of learning each step of these surgical techniques. A review of the developmental process of this operation leads to recognition of the tips, pitfalls, and solutions. We review here the principal concepts of TES for spinal tumors, as well as their related basic works that support the rationality of this operation.

Total en bloc spondylectomy for spinal metastases in thyroid carcinoma.

OBJECT Thyroid carcinoma generally has a favorable prognosis, and patients rarely present with distant metastases. Authors of several studies have proposed piecemeal resection for spinal metastases in thyroid carcinoma; however, few have analyzed the impact of local curative surgery such as total en bloc spondylectomy (TES) for thyroid carcinoma. The purposes of the present study are to determine the strategy of surgical treatment for spinal metastases of thyroid carcinoma and to evaluate the surgical results of and the prognosis associated with TES. METHODS Twenty-four cases of spinal metastases were retrospectively reviewed. The patients included 16 women and 8 men, with a mean age of 60.7 years. Histological examination showed follicular carcinoma in 15 cases, papillary carcinoma in 8, and medullary carcinoma in 1. Total en bloc spondylectomy was performed in 10 cases; debulking surgery, such as piecemeal excision or eggshell curettage, was performed in 14. The average follow-up time was 55 months (12-180 months). RESULTS Four patients had no evidence of disease, 8 were alive with the disease, and 12 had died of the disease. The overall survival rate from the time of surgery was 74% at 5 years. Patients with visceral metastases had a significant, higher risk of death. The survival rate of patients following TES was 90% at 5 years, which was higher than the rate in patients who underwent debulking surgery (63%). However, no significant difference was observed between the 2 types of surgery. There was a local recurrence after debulking surgery in 8 (57%) of 14 cases. Because of the recurrences, reoperation was required after a mean of 41 months. In contrast, there was a local recurrence after TES in only 1 (10%) of 10 cases. The difference between debulking surgery and TES regarding local recurrence was statistically significant. CONCLUSIONS Total en bloc spondylectomy with enough of a margin provided favorable local control of spinal metastases of thyroid carcinoma during a patients lifetime.

Effects on spinal cord blood flow and neurologic function secondary to interruption of bilateral segmental arteries which supply the artery of Adamkiewicz: an experimental study using a dog model.

Study Design. Segmental arteries including the level of Adamkiewicz artery were interrupted bilaterally for up to 4 levels to study the effects on spinal cord blood flow and neurologic function in dogs. Objective. To examine how many ligations of bilateral segmental arteries including the level of Adamkiewicz artery cause ischemic spinal cord dysfunction. Summary of Background Data. Interruption of bilateral segmental arteries at ≥5 consecutive levels without the level of Adamkiewicz artery has been reported to risk producing ischemic spinal cord dysfunction in dog model. However, the effects of ligating including the level of Adamkiewicz artery have not been elucidated. Methods. The 25 dogs in which Adamkiewicz artery originated from L5 level were taken in this study. There were 15 dogs divided into 5 groups: sham group, no ligation; group 1, ligation of bilateral segmental arteries at 1 level (L5); group 2, at 2 levels (L4–L5); group 3, at 3 levels (L4–L6); and group 4, at 4 levels (L3–L6). Spinal cord blood flow at the L5 spinal cord segment by laser-Doppler flowmetry, and spinal cord-evoked and compound muscle action potentials were measured simultaneously until 10 hours after ligation. Neurologic function was assessed using a modified Tarlov grading system 1 week after operation in 10 other dogs divided into 2 groups: 3 pairs group, ligation at 3 levels (L4–L6); 4 pairs group, at 4 levels (L3–L6). Results. Spinal cord blood flow was 98.2%, 76.1%, 66.6%, 61.4%, and 53.5% in the sham group, groups 1, 2, 3, and 4, respectively, 10 hours after ligation. Abnormal spinal cord-evoked and compound muscle action potentials were observed in 1 out of 3 dogs in group 4. Postoperative neurologic evaluation identified all 5 dogs in 3 pairs group and 4 in 4 pairs group as having grade 5. There was 1 dog in 4 pairs group that had grade 4. Conclusion. Interruption of bilateral segmental arteries at ≥4 consecutive levels including the level of Adamkiewicz artery risks producing ischemic spinal cord dysfunction.

Total en bloc spondylectomy for lung cancer metastasis to the spine.

OBJECT The prognosis in patients with a distant spinal metastasis from the lung is dismal. The role of radical surgery in such cases has been questioned because of the excessive morbidity, blood loss, and operative time as well as the tumors extreme malignancy. The purpose of this study was to evaluate the surgical results and the prognosis associated with radical surgery for lung cancer metastasis to the spine in carefully selected patients and to clarify whether there is an indication for radical surgery such as total en bloc spondylectomy (TES) in lung cancer metastasis. METHODS The author performed a retrospective review of patients with lung cancer spinal metastasis treated by TES during a 10-year period. Total en bloc spondylectomy for lung cancer metastasis to the spine was performed in 6 patients without visceral or other bony metastases. Outcome measures were prognostic score, mean survival time, and perioperative complications. The histological type was adenocarcinoma in all 6 cases. In 4 cases the surgical strategy prognostic score was 5. In the other 2 cases the score was 6 because there were skip metastases to adjacent vertebra. In the 2 cases with adjacent vertebral metastasis, the adjacent vertebra was excised en bloc together. RESULTS The mean estimated blood loss was 1076 ml and the mean operative time was 7 hours 20 minutes. Perioperative complications were found in 2 cases. One was deep infection after CSF leakage, and the other was paralysis due to postoperative hematoma. At the end of follow-up period, 4 of 6 patients are still living after a mean of 46.3 months (range 36–62 months). In the other 2 cases, 1 patient died of a heart attack and the other of mediastinitis due to surgical site infection by methicillin-resistant Staphylococcus aureus. In this series, local recurrence was not found. CONCLUSIONS Total en bloc spondylectomy has been shown to be associated with excessive morbidity, blood loss, and operative time; however, the procedure is becoming less invasive. The authors conclude that TES is appropriate in selected cases with controllable primary lung cancer, localized spinal metastasis, and no visceral metastasis. In such patients, improvement in the prognosis can be expected after TES. However, even in selected cases and with skilled surgical technique, the complication rate remains high. Total en bloc spondylectomy should be performed after a thorough discussion of the risks and benefits.

Surgical management of aggressive vertebral hemangiomas causing spinal cord compression: long-term clinical follow-up of five cases

BackgroundAggressive vertebral hemangiomas causing spinal compression are rare, and there is controversy with regard to treatment. The purpose of this study was to evaluate the clinical results of patients with aggressive vertebral hemangiomas at a mean follow-up of more than 10 years after total excision and discuss the treatment options for the tumors.MethodsWe performed a retrospective review of patients with aggressive vertebral hemangiomas who were treated with total excision. The surgeries were carried out on five patients (average age 47 years). In all five patients, the tumor was in the thoracic spine and was causing myelopathy with extraosseous extension. There were three tumors of type 5 and two of type 6 according to Tomita’s surgical classification of spinal tumors. The tumors were assessed using magnetic resonance imaging (MRI), and the clinical results were evaluated.ResultsAll of the tumors showed low-intensity or low-isointensity signal on T1-weighted MRI. All five patients had a combination of preoperative transarterial embolization and total excision including tumor margin. Total en bloc excisions were performed in two patients. En bloc and piecemeal combined total excisions were performed in two patients. Piecemeal total excision was performed in one patient. Intraoperative blood loss ranged from 1580 to 3400 ml (mean 2424 ml). There were no perioperative complications. According to the Japanese Orthopaedic Association score, the myelopathy improved after the surgery from 5.3 ± 2.9 to 9.8 ± 1.7 (total of 11 points). None of the patients have had a recurrence at a mean followup of 135.2 months (range 92–163 months).ConclusionsWe performed a combination of preoperative transarterial embolization and total excision for aggressive vertebral hemangiomas with extraosseous extension that were causing spinal cord compression in all five cases. The results in the long-term follow-up have proved satisfactory.

Total en bloc spondylectomy of the lower lumbar spine: a surgical techniques of combined posterior-anterior approach.

Study Design. Ten patients with a spinal tumor of the lower lumbar spine underwent total en bloc spondylectomy (TES) by combined posterior-anterior approach. The oncological and neurologic results are analyzed. Objective. To describe the surgical technique and evaluate the clinical outcome of this surgery. Summary of the Background Data. TES at lower lumbar spine is technically challenging because of its anatomy such as the presence of major vessels and lumbosacral plexus nerves. Methods. Six aggressive benign tumors and 4 solitary spinal metastases involving L4 or L5 were treated. The approache of operative procedure are discussed as follows: Posterior approach: Dissection of the lumbar nerve roots to the conjunction of the adjacent nerves were performed after en bloc laminectomy by T-saw pediculotomy. The psoas muscle was dissected away, from the vertebral body. The posterior halves of the anterior column at the craniocaudal adjacent levels of the lumbar tumor were cut. Anterior approach: Major vessels were dissected from the vertebral body. Anterior halves of the anterior column were cut at the corresponding levels. The tumor vertebral body was removed en bloc, followed by anterior spinal reconstruction. Results. Seven of 10 cases had no evidence of disease at 57 months on average, 1 case was alive with disease at 66 months, 1 case had death of disease at 42 months, and 1 case had death of another disease at 14 months after surgery. All patients improved or preserved neurologic in the last follow up. The resected specimen of vertebral bodies and laminae showed marginal or wide margin in all cases, although pedicles showed intralesional margin in 8 cases. No local recurrence was observed during lifetime with mean 52 months. Conclusion. TES for spinal tumor of L4 or L5 preserving lumbar nerves was achieved by combined posterior- anterior approach.

Does interruption of the artery of Adamkiewicz during total en bloc spondylectomy affect neurologic function

Study Design. A retrospective review of patients with interruption of the artery of Adamkiewicz during total en bloc spondylectomy (TES). Objective. To assess neurologic function after interruption of the artery of Adamkiewicz in TES. Summary of Background Data. The most important feeding artery of the thoracolumbar spinal cord is the great anterior radiculomedullary artery, also called the artery of Adamkiewicz. The artery of Adamkiewicz supplies the lower two-thirds of the spinal cord via the anterior spinal artery. It is naturally believed among spine surgeons that interruption of the artery of Adamkiewicz during surgeries is absolutely contraindicated. However, it is necessary to sacrifice the artery of Adamkiewicz during TES, when the tumor, by chance, exists at the level of the artery of Adamkiewicz. Methods. Between 1990 and 2009, we have performed 180 cases of TES. All cases except for few emergency cases received preoperative embolization. The artery of Adamkiewicz was verified by angiography of the segmental arteries. There were 15 patients in which the artery of Adamkiewicz was found at the levels of resected vertebrae. Interruption of the artery was performed during surgery in these 15 cases. Neurologic function was analyzed retrospectively. Results. Of the 15 patients, the Frankel grade before surgery was C in 1, D in 5, and E in 9. At follow-up, the Frankel grade was D in 1 and E in 14. There were no cases of neurologic deterioration or paralysis after TES. Conclusion. On the basis of our results of TES on up to 3 vertebrae, interruption of the artery of Adamkiewicz for TES does not adversely affect neurologic function. We advocate strongly that our surgeons are allowed to sacrifice up to 3 pairs of segmental arteries, even including the artery of Adamkiewicz, if necessary.

Preoperative embolization significantly decreases intraoperative blood loss during palliative surgery for spinal metastasis.

Several studies have evaluated the efficacy of preoperative embolization in devascularizing tumors. However, no study has measured intraoperative blood loss in a single palliative surgery compared with a control group without preoperative embolization. The purpose of this retrospective study was to evaluate the efficacy of preoperative embolization on intraoperative blood loss in palliative decompression and instrumented surgery using a posterior approach for spinal metastasis. Between 2000 and 2010, forty-six patients underwent palliative decompression and instrumented surgery using a posterior approach for spinal metastasis in the thoracic and lumbar spine. Preoperative embolization was performed in 23 patients (embolization group), and surgery was performed within 3 days after embolization. The embolic materials used were polyvinyl alcohol particles, gelatin sponge, and metallic coils. Twenty-three patients did not undergo embolization (no embolization group). Pain and neurologic symptoms in all 46 patients were relieved postoperatively. Average intraoperative blood loss was 520 mL (range, 140-1380 mL) in the embolization group and 1128 mL (range, 100-3260 mL) in the no embolization group (P<.05). In the embolization group, intraoperative blood loss was not correlated with the degree of tumor vascularization, completeness of embolization, or time between embolization and surgery. Intraoperative blood loss after preoperative embolization was less than half that after no preoperative embolization.

Neurological function after total en bloc spondylectomy for thoracic spinal tumors.

OBJECT Total en bloc spondylectomy (TES) for thoracic spinal tumors may in theory produce neurological dysfunction as a result of ischemic or mechanical damage to the spinal cord. Potential insults include preoperative embolization at 3 levels, intraoperative ligation of segmental arteries, nerve root ligation, and circumferential dural dissection. The purpose of this study was to assess neurological function after thoracic TES. METHODS The authors performed a retrospective review of 79 patients with thoracic-level spinal tumors that had been treated with TES between 1989 and 2006. Neurological function was retrospectively analyzed according to the Frankel grading system. Of the 79 cases, 26 involved primary tumors and 53 involved metastatic tumors. The number of excised vertebrae was 1 in 60 cases, 2 in 13, and >or= 3 in 6. The Frankel grade before surgery was B in 1 case, C in 16, D in 29, and E in 33. RESULTS At the follow-up, the Frankel grade was C in 2 cases, D in 24, and E in 53. Of 46 cases with neurological deficits before surgery, neurological improvement of at least 1 Frankel grade was achieved in 25 cases (54.3%). Although the Frankel grade did not change in 21 patients, improvement in neurological symptoms within the same Frankel grade did occur in these patients. There were no cases of neurological deterioration. CONCLUSIONS There was no neurological deterioration due to preoperative embolization, ligation of segmental arteries, or ligation of thoracic nerve roots. Each of the cases with preoperative neurological deficits showed improvement in neurological symptoms. Data in the current study clinically proved that TES is a safe operation with respect to spinal cord blood flow. In TES, the spinal cord is circumferentially decompressed and the spinal column is shortened. An increase in spinal cord blood flow due to spinal shortening in addition to decompression was considered to have brought about a resolution of neurological symptoms with TES.

Venous thromboembolism after spine surgery: changes of the fibrin monomer complex and D-dimer level during the perioperative period

OBJECT The goal of this study was to determine the incidence of deep venous thrombosis (DVT) and pulmonary embolism (PE) after spine surgery. Another purpose was to clarify the rapid changes of the fibrin monomer complex (FMC) and D-dimer levels during the perioperative period of spine surgery for early diagnosis of venous thromboembolism (VTE). METHODS The participants were 72 patients who underwent spine surgery between September 2007 and March 2008. The FMC and D-dimer levels were measured 6 times: 1) at induction of general anesthesia; 2) just after implantation or during surgery; 3) immediately following surgery; 4) 1 day after surgery; 5) 3 days postsurgery; and 6) 7 days after surgery. All patients received mechanical prophylaxis, including compression stockings and intermittent pneumatic compression devices, and all were examined with duplex ultrasonography assessments of both lower extremities and with lung perfusion scintigraphy 7-10 days after surgery. If DVT or PE was suspected, the patient underwent multidetector CT venography. RESULTS There were no patients with clinical signs of DVT and PE, but 6 (8.3%) showed VTE, among whom 5 had DVT and 3 had PE. Patients with VTE had significantly higher FMC levels 1 day after surgery, compared with those without VTE (55.9 ± 17.2 μg/ml vs 11.1 ± 2.89 μg/ml; p < 0.01). Patients with VTE had significantly higher D-dimer levels 7 days postsurgery, compared with those without VTE (12.5 ± 2.95 μg/ml vs 4.3 ± 0.39 μg/ml; p < 0.01). Receiver operating characteristic analysis showed that the FMC result was more useful than the D-dimer assay for diagnosis of VTE. When the cutoff value was set to 20.8 μg/ml for FMC, sensitivity was 100% and specificity was 86.3%. CONCLUSIONS In this study the prevalence of VTE after spine surgery was 8.3%. The FMC measured 1 day after spine surgery is considered to be useful as an indicator of VTE.