Noriaki Yokogawa

Perioperative Complications of Total En Bloc Spondylectomy: Adverse Effects of Preoperative Irradiation

Background Total en bloc spondylectomy (TES) is associated with a high complication rate because it is technically demanding and involves patients compromised by cancer. Specifically, perioperative complications are more likely to occur in patients receiving preoperative irradiation. We examined the perioperative complications associated with TES in patients receiving preoperative irradiation. Methods Seventy-seven patients underwent TES between May 2010 and April 2013. We performed a retrospective review of prospectively collected data for 50 patients with metastatic tumors of the thoracic spine, excluding patients with primary spinal tumors, lumbar spinal metastasis, and combined anterior and posterior approach TES. Patients were divided into 2 groups: those with preoperative irradiation (RT-TES group, 18 patients) and those without preoperative irradiation (TES group, 32 patients). The following perioperative complications, occurring within 2 months of surgery, were compared between the groups: intraoperative dural injuries, epidural hematomas, deep surgical-site infections, postoperative cerebrospinal fluid leakage, wound dehiscence, pleural effusions, and neurological deficits. Results Significant differences in patient characteristics were not observed between the RT-TES and TES groups. Perioperative TES complications occurred in 20/50 patients (40.0%). The complication rate in the RT-TES group was 77.8% (14 out of 18), threefold higher than the 18.8% (6 out of 32) in the TES group (P<0.01). The incidence of complications, including intraoperative dural injuries, postoperative cerebrospinal fluid leakage, wound dehiscence, and pleural effusions, was significantly higher in the RT-TES group (P<0.01). Conclusion The perioperative complication rate associated with TES for spinal metastasis was significantly higher among patients receiving preoperative irradiation than among those not receiving preoperative irradiation.

Surgical site infection after total en bloc spondylectomy: risk factors and the preventive new technology.

BACKGROUND CONTEXT Surgical site infection (SSI) associated with instruments remains a serious and common complication in patients who undergo total en bloc spondylectomy (TES). It is very important that the risk factors for SSI are known to prevent it. PURPOSE The purpose of the study was to identify independent risk factors for SSI after TES and evaluate the positive effect of iodine-supported spinal instruments in the prevention of SSI after TES. STUDY DESIGN This is a retrospective clinical study. PATIENT SAMPLE One hundred twenty-five patients who underwent TES for vertebral tumor were evaluated. OUTCOME MEASURES Incidence rate of SSI, risk factors for SSI after TES, and safety of iodine-supported spinal instruments were the outcome measures. METHODS Risk factors for SSI were analyzed using logistic regression. In recent 69 patients with iodine-supported spinal instruments, the thyroid hormone levels in the blood were examined to confirm if iodine from the implant influenced thyroid function. Postoperative radiological evaluations were performed regularly. RESULTS The rate of SSI was 6.4% (8/125 patients). By multivariate logistic regression, combined anterior and posterior approach and nonuse of iodine-supported spinal instruments were associated with an increased risk of SSI. The rate of SSI without iodine-supported spinal instruments was 12.5%, whereas the rate with iodine-supported spinal instruments was 1.4%. This difference was statistically significant. There were no detected abnormalities of thyroid gland function with the use of iodine-supported instruments. Among the 69 patients with iodine-supported spinal instruments, 2 patients required additional surgery because of instrument failure. However, there were no obvious involvements with the use of iodine-supported spinal instruments. CONCLUSIONS This study identified combined anterior and posterior approach and nonuse of iodine-supported spinal instruments to be independent risk factors for SSI after TES. Iodine-supported spinal instrument was extremely effective for prevention of SSI in patients with compromised status, and it had no detection of cytotoxic or adverse effects on the patients.

Increase of IL-12 following Reconstruction for Total En Bloc Spondylectomy Using Frozen Autografts Treated with Liquid Nitrogen

Background Total en bloc spondylectomy (TES) is a surgery designed to achieve complete resection of a malignant spinal tumor such as spinal metastasis. Although this procedure decreases the rate of local recurrence, it is questionable whether local control prolongs patient’s survival. We developed a “second-generation TES” that brings about TES enhancing antitumor immunity to prolong patient’s survival. Our purpose is to present a second-generation TES applied tumor-induced cryoimmunology and assess the immunity-enhancing effect after implementing this surgery. Methods We performed a retrospective review of prospectively collected data in second-generation TES as carried out in 56 cases. In second-generation TES, instead of harvesting autograft from the ilium or fibula, the resected lamina and vertebral body from TES are frozen using liquid nitrogen and used as grafted bone for spinal reconstruction. In recent 26 of the 56 cases, in addition to the TES procedure, a small amount of the tumor tissue from the resected tumor-bearing vertebra was also placed into liquid nitrogen. This small amount of tumor tissue was then implanted subcutaneously on one side of the axilla. In 52 of 56 cases, measurement of interleukin 12 (IL-12) was performed before surgery and at both 1 and 3 months after surgery. Results IL-12 increased after TES surgery in 38 of 52 cases (73.1%). The mean IL-12 relative concentrations at both 1 and 3 months after surgery, as compared to before surgery, were significantly higher (121±89 and 149±111%: P<0.05 and P<0.01). Conclusions Our results show that second-generation TES may provide not only a local radical cure but also a systemic immunological enhancement. Further prolonged survival in patients with a malignant spinal tumor is promising by second-generation TES.

Influence of Rod Contouring on Rod Strength and Stiffness in Spine Surgery.

For spinal fusion or the correction of spine deformity at multiple levels, intraoperative rod contouring is required to realign the spine. A French bender is the most common contouring tool used. There are several reports on the mechanical properties of various rods with manufactured straight rod; however, few reports describe the changes in a rods mechanical properties after rod contouring. The authors investigated the influences of rod contouring on rod strength and stiffness. A 3-point bending test was conducted. Each 18-cm rod was loaded at a rate of 10 mm/min with a load applicator. Three different rod diameters (5.5, 6.0, and 6.35 mm) and 2 types of materials (titanium [Ti] alloy and cobalt-chromium [CoCr] alloy) were assessed. Different rod curvatures were evaluated: (1) a no-preparation rod of 0° (control); (2) a 0° rod bent at one point to make tangential angles of 10° and then bent back from the opposite side; (3) a bent rod with tangential angles of 20°; and (4) a 40° bent rod. The yield strength in all types of rod materials and diameter decreased after rod contouring using a French bender. The extent of decrease depended on the degree of bend. The bending stiffness of each rod also decreased. The CoCr rod showed higher bending stiffness than the Ti rod of the same diameter. Rod contouring using a French bender reduced the yield strength and stiffness in all types of rods. Decrease of yield strength correlated to the degree of bend. In the comparison of 20° and 40° contoured rods, the 6.0-mm CoCr rod showed the highest reduction force. This study found that rod contouring procedures reduced rod yield strength and stiffness.

Effects of Radiation on Spinal Dura Mater and Surrounding Tissue in Mice.

Purpose Spinal surgery in a previously irradiated field carries increased risk of perioperative complications, such as delayed wound healing or wound infection. In addition, adhesion around the dura mater is often observed clinically. Therefore, similar to radiation-induced fibrosis—a major late-stage radiation injury in other tissue—epidural fibrosis is anticipated to occur after spinal radiation. In this study, we performed histopathologic assessment of postirradiation changes in the spinal dura mater and peridural tissue in mice. Materials and Methods The thoracolumbar transition of ddY mice was irradiated with a single dose of 10 or 20 Gy. After resection of the irradiated spine, occurrence of epidural fibrosis and expression of transforming growth factor beta 1 in the spinal dura mater were evaluated. In addition, microstructures in the spinal dura mater and peridural tissue were assessed using an electron microscope. Results In the 20-Gy irradiated mice, epidural fibrosis first occurred around 12 weeks postirradiation, and was observed in all cases from 16 weeks postirradiation. In contrast, epidural fibrosis was not observed in the nonirradiated mice. Compared with the nonirradiated mice, the 10- and 20-Gy irradiated mice had significantly more overexpression of transforming growth factor beta 1 at 1 week postirradiation and in the late stages after irradiation. In microstructural assessment, the arachnoid barrier cell layer was thinned at 12 and 24 weeks postirradiation compared with that in the nonirradiated mice. Conclusion In mice, spinal epidural fibrosis develops in the late stages after high-dose irradiation, and overexpression of transforming growth factor beta 1 occurs in a manner similar to that seen in radiation-induced fibrosis in other tissue. Additionally, thinning of the arachnoid barrier cell layer was observed in the late stages after irradiation. Thus, consideration should be given to the possibility that these phenomena can occur as radiation-induced injuries of the spine.

Motor function of the upper-extremity after transection of the second thoracic nerve root during total en bloc spondylectomy

Background In total en bloc spondylectomy (TES) of upper thoracic spine including the second thoracic (T2) vertebra, T2 nerve roots are usually transected. In this study, we examined the association between transection of the T2 nerve roots and upper-extremity motor function in patients with upper thoracic TES. Methods We assessed 16 patients who underwent upper thoracic TES with bilateral transection of the T2 nerve roots. Patients were divided into three groups: 3 patients without any processing of T1 and upper nerve roots (T2 group), 7 with extensive dissection of T1 nerve roots (T1–2 group), and 6 with extensive dissection of T1 and upper nerve roots (C–T2 group). Postoperative upper-extremity motor function was compared between the groups. Results Postoperative deterioration of upper-extremity motor function was observed in 9 of the 16 patients (56.3%). Three of the 7 patients in the T1–2 group and all 6 patients in the C–T2 group showed deterioration of upper-extremity motor function, but there was no deterioration in the T2 group. In the T1–2 group, 3 patients showed mild deterioration that did not affect their activities of daily living and they achieved complete recovery at the latest follow-up examination. In contrast, severe dysfunction occurred frequently in the C–T2 group, without recovery at the latest follow-up. Conclusions The transection of the T2 nerve roots alone did not result in upper-extremity motor dysfunction; rather, the dysfunction is caused by the extensive dissection of the T1 and upper nerve roots. Therefore, transection of the T2 nerve roots in upper thoracic TES seems to be an acceptable procedure with satisfactory outcomes.

Differences in Gait Characteristics of Patients with Lumbar Spinal Canal Stenosis (L4 Radiculopathy) and Those with Osteoarthritis of the Hip.

It is important to differentially diagnose thigh pain from lumbar spinal stenosis (particularly lumbar fourth nerve root radiculopathy) and osteoarthritis of the hip. In this study, using a treadmill and a motion analysis method, gait characteristics were compared between these conditions. Patients with lumbar fourth nerve root radiculopathy had increased physiological knee flexion immediately after foot-ground contact, possibly owing to a slight decrease in the muscle strength of the quadriceps femoris muscle. Patients with osteoarthritis of the hip had decreased range of motion of the hip joint probably due to anatomically limited mobility as well as gait strategy to avoid pain resulting from increased internal pressure on the hip joint during its extension. Our facile and noninvasive method can be useful for the differential diagnosis of lumbar spinal canal stenosis from osteoarthritis of the hip.

Vertebral Osteomyelitis Caused by Mycobacterium abscessus Surgically Treated Using Antibacterial Iodine-Supported Instrumentation

Mycobacterium abscessus infections rarely develop in healthy individuals, and mostly they occur in immunocompromised hosts. Vertebral osteomyelitis due to Mycobacterium abscessus is very rare and only three previous cases of spinal infection caused by Mycobacterium abscessus have been reported. Mycobacterium abscessus isolates are uniformly resistant to antituberculous agents and can display a virulent biofilm-forming phenotype. The patient was a 67-year-old woman with vertebral osteomyelitis of the L1-2. She was healthy without immune-suppressed condition, history of trauma, or intravenous drug use. The smear examination of the specimen harvested by CT-guided puncture of the paravertebral abscess revealed Mycobacterium abscessus. Her disease condition did not abate with conservative treatment using antimicrobial chemotherapy. Radical debridement of the vertebral osteomyelitis and anterior reconstruction from T12 to L2 using antibacterial iodine-supported instrumentation were performed. Chemotherapy using clarithromycin, amikacin, and imipenem was applied for 6 months after surgery as these antibiotics had been proven to be effective to Mycobacterium abscessus after surgery. Two years after surgery, the infected anterior site healed and bony fusion was successfully achieved without a recurrence of infection.

Novel reconstruction technique using a frozen tumor-bearing vertebra from a total en bloc sponydylectomy for spinal tumors.

This article describes a novel reconstruction technique using frozen tumor-bearing vertebrae in total en bloc spondylectomy for spinal tumors. Instead of harvesting autograft from the ilium or fibula, the resected lamina and vertebral body from the total en bloc spondylectomy are frozen in liquid nitrogen and used as grafted bone for spinal reconstruction. A retrospective review of 56 patients was undertaken. As a result of this review, it was determined that this technique has the benefits of no pain at the bone harvest site, shortened operative time, decreased blood loss, and an additional antitumor immune response.

Walking motion analysis of intermittent claudication and its application to medical diagnosis

There are mainly two kinds of diseases in intermittent claudication. One is lumbar spinal canal stenosis (LSS) and the other is peripheral arterial disease (PAD). Differentiating LSS and PAD is a critical issue. Wrong differentiation might cause amputation of lower extremities. At small clinics and hospitals, simple and cheap differentiation system is required. Concerning this, this paper investigated walking motions of the patients. The subject with LED markers walked on the treadmill until she or he felt pain. We recorded the walking motion by camera and tracked the LED markers. Treadmill enables to measure walking motion for a long time in a small space, and LED marker provides position of every joint in the walking. Then, we can get the information such as joint angle trajectory, hemi-foot step, stance and swing phases without any other sensors like foot switch or force plate. We compared walking motions of healthy persons, LSS patients and PAD patients, found their features and 3 factors for disease differentiation; average bending angle of knee joint at the start of stance phase, average dorsiflexion angle of ankle joint, and average hemi-foot step length. The results indicate that 2 dimensional images of walking motion for several seconds are enough for deriving the factors. Then, we can construct the simple examination system for the disease differentiation.