Article Access Statistics    Viewed160        Printed24        Emailed0        PDF Downloaded9        Comments [Add]    

Click on image for details.

 

      ORIGINAL ARTICLE Year : 2022  |  Volume : 70  |  Issue : 8  |  Page : 230-238

Analysis of Nanohydroxyapatite/Polyamide-66 Cage, Titanium Mesh, and Iliac Crest in Spinal Reconstruction of the Patients with Thoracic and Lumbar Tuberculosis

Dian Zhong, Lu Lin, Yang Liu, Zhen-Yong Ke, Yang Wang
Department of Orthopedic Surgery, The Second Affiliated Hospital of Chongqing Medical University, Yuzhong District, Chongqing, China

Date of Submission27-Jan-2022Date of Decision02-Jun-2022Date of Acceptance09-Jun-2022Date of Web Publication11-Nov-2022

Correspondence Address:
Yang Wang
Department of Orthopedic Surgery, The Second Affiliated Hospital of Chongqing Medical University, No. 76, Linjiang Road, Yuzhong District, Chongqing - 400010
China

Source of Support: None, Conflict of Interest: None

Check

DOI: 10.4103/0028-3886.360908

Background: The standard recommended and common reconstruction method for spinal tuberculosis is titanium mesh bone graft and autogenous iliac crest. However, these methods have their own disadvantages.
Objective: To evaluate the clinical efficacy of one-stage posterior debridement with iliac bone graft, titanium mesh bone graft, or nanohydroxyapatite/polyamide-66 cage in thoracic and lumbar tuberculosis.
Materials and Methods: Between January 2013 and December 2018, 57 patients with thoracic or lumbar tuberculosis were treated by interbody bone graft combined with posterior internal fixation after debridement. Thirteen patients were treated with iliac bone graft to construct the stability of the vertebral body, 26 patients were treated with titanium mesh bone graft, and 18 patients were treated with nanohydroxyapatite/polyamide-66 cage bone graft. The main clinical results were evaluated by intervertebral height, cage subsidence, operation time, operative blood loss, postoperative hospitalization, postoperative complications, visual analog scale (VAS) score, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), American Spinal Injury Association (ASIA) grade, and bone graft fusion time. All the outcomes were recorded and analyzed by statistical methods.
Results: The mean follow-up time was 24.5 months. Neurologic function was improved in most patients at the last follow-up. There were significant differences in ESR, CRP, and VAS score between preoperative and postoperative values; however, there were no significant differences in ESR, CRP, and VAS score among the three groups. There were no significant differences in operation time, blood loss, postoperative hospitalization, and postoperative complications among the three groups at discharge. There was no significant difference in ASIA grade among the three groups at the last follow-up. Nanohydroxyapatite/polyamide-66 cage group had a lower cage subsidence (P = 0.013). The bone graft fusion time of the nanohydroxyapatite/polyamide-66 cage group was significantly shorter than the iliac bone graft group and the titanium mesh bone graft (P < 0.05).
Conclusions: The follow-up outcomes showed that the method involving one-stage posterior debridement and internal fixation, interbody graft, and fusion is an effective and safe surgical method for patients with thoracic and lumbar tuberculosis. The incidence rate of cage subsidence was less and the bone graft fusion time was shorter with nanohydroxyap atite/polyamide 66 cage when compared with iliac bone graft and titanium mesh bone graft in the surgical treatment of thoracic and lumbar tuberculosis. Nanohydroxyapatite/polyamide-66 cage has a promising application prospect to be a new bone graft material.

Keywords: Bone Graft Material, nanohydroxyapatite/polyamide-66 cage, posterior debridement, thoracolumbar tuberculosis, titanium mesh cage
Key Message: Surgical treatment can resect the lesions thoroughly, control the progression of the disease, promote bone fusion of intervertebral graft and reduce the likelihood of recurrence of spinal tuberculosis.

How to cite this article:
Zhong D, Lin L, Liu Y, Ke ZY, Wang Y. Analysis of Nanohydroxyapatite/Polyamide-66 Cage, Titanium Mesh, and Iliac Crest in Spinal Reconstruction of the Patients with Thoracic and Lumbar Tuberculosis. Neurol India 2022;70, Suppl S2:230-8
How to cite this URL:
Zhong D, Lin L, Liu Y, Ke ZY, Wang Y. Analysis of Nanohydroxyapatite/Polyamide-66 Cage, Titanium Mesh, and Iliac Crest in Spinal Reconstruction of the Patients with Thoracic and Lumbar Tuberculosis. Neurol India [serial online] 2022 [cited 2022 Nov 16];70, Suppl S2:230-8. Available from: https://www.neurologyindia.com/text.asp?2022/70/8/230/360908

Tuberculosis (TB), a common infectious disease in developing countries, also shows a gradually increasing trend in developed countries because of the presence of human immunodeficiency virus (HIV) infection and drug resistance, which also pose new challenges in developed nations.[1],[2] Spinal TB (STB) is a tissue-destroying disease that destroys the intervertebral discs and adjacent vertebral bodies. It accounts for approximately 50% of osteoarticular tuberculosis.[3],[31] STB might lead to devastating outcomes including kyphosis, compression of the spinal cord, and the formation of cold abscesses.[4],[32] Anti-TB chemotherapy remains the mainstream of treatment. However, patients with STB often have severe nerve impairment, spinal instability, and kyphosis. Therefore, surgical management is paramount for radical debridement, decompression of neural elements, correction of deformity, reconstruction of the anterior column, and stable fusion.[5],[6] Currently, anti-TB chemotherapy combined with radical surgical procedure is used by most medical institutions, which is recognized as the optimal treatment option.[1],[33],[34] Thorough resection of the lesions can control the progression of the disease, promote bone fusion of intervertebral graft, and reduce the likelihood of recurrence of STB.[7] However, thorough resection of the lesions will lead to vertebral defect and destroy the pedicles and tissues. So, proper bone grafts are necessary to repair the vertebral defect and reconstruct stability. Although great advances have been made in surgical techniques and bone graft materials, many implant-related complications such as chronic pain of donor site, nonunion, displacement of the bone graft materials, and cage subsidence have been frequently reported.[8],[9],[35] To address these issues, various bone graft materials such as autogenous ribs, autogenous iliac crest, allograft, titanium mesh cages, and other grafting materials have been developed. However, the choice of bone graft materials in an infected area remains a matter of debate. At present, the most commonly used bone graft material in STB surgery is titanium mesh cage (TMC), which has been widely used for decades due to its excellent biomechanical properties and biocompatibility.[10],[11] However, stress shielding, high incidence of cage subsidence, lack of tissue adherence,[11] and postoperative radiographic interference obstruct TMC from becoming an ideal reconstruction bone graft material. At the same time, the use of autogenous bone grafts from the iliac crest has long been considered as another alternative method. The tricortical iliac crest graft could achieve satisfactory osseous fusion due to the osteoinductive and osteogenetic properties; however, concerns over chronic donor site pain or infection pose big challenges.[12],[36] In recent years, nanohydroxyapatite (n-HA)/polyamide-66 (PA66) cage (n-HA/PA66 cage), a novel biomimetic nonmetal cage device, has shown competitive clinical efficacy in many medical centers.[7],[8],[10] It provides more choices for posterior reconstruction to ensure satisfactory osseous fusion and reduce the complications, compared with traditional bone graft material. The chemical composition of the n-HA/PA66 cage is similar to the natural bone, which is made by covalent miscibility of n-HA and PA66.[13],[37],[38] This cage has the advantage of preventing subsidence and migration by decreasing the cutting action and increasing friction between the vertebra and cage edges because of its characteristic design of several shallow recesses. However, detailed comparisons of the n-HA/PA66 cage with other bone graft materials have not been reported. The difference in clinical efficacy among n-HA/PA66 cage bone graft, iliac bone graft, and TMC bone graft combined with internal fixation after debridement remains unclear. In this study, we aimed to evaluate the clinical efficacy of n-HA/PA66 cage bone graft, iliac bone graft, and TMC bone graft in the treatment of thoracic and lumbar TB.

  Materials and Methods 

The inclusion criteria included single-segment or two-segment thoracic and thoracolumbar TB confirmed by postoperative histopathologic examination, one-stage posterior debridement, internal fixation, and reconstruction using TMCs, autogenous iliac crest, or n-HA/PA66 cages. The follow-up time was more than 6 months. The exclusion criteria included active pulmonary TB, malignant tumor, and discontinuous multisegment STB. Between January 2013 and December 2018, 57 patients with thoracic and lumbar TB were treated by interbody bone graft combined with one-stage posterior internal fixation after debridement. Of those, most patients had typical symptoms of STB, including night fever, loss of weight and back pain. The T-SPOT TB test was used to screen the presence of TB. X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) of the thoracic or lumbar spine were performed on all the patients to evaluate the destruction degree of the vertebral body, the degree of intervertebral space narrowing, and spinal cord compression. The American Spinal Injury Association (ASIA) neurological classification was routinely used to evaluate the degree of neurological dysfunction, and the visual analog scale (VAS) was used to evaluate the degree of pain before and after surgery. Preoperative and postoperative Cobb angle was measured on lateral X-ray to evaluate the degree of kyphosis correction. X-ray and CT images in the follow-up time were used to observe the degree of bony fusion.

Preoperative management

Before surgery, all patients were prescribed anti-TB chemotherapy of isoniazid (INH; 5 mg/kg), rifampicin (10 mg/kg), pyrazinamide (25 mg/kg), and ethambutol (15 mg/kg) for at least 2 weeks, until the erythrocyte sedimentation rate (ESR) decreased below 40 mm/h, the related symptoms of TB were relieved progressively, and other conditions were suitable for surgery. If there was no significant decrease in the ESR or the symptoms of TB poisoning were not improved, levofloxacin injection (intravenous drip, 400 mg/d) was added to reinforce the effect of drug therapy. For those patients who had a neurological worsening in a very short time, surgery was performed as soon as possible to achieve early spinal cord decompression. In this case, conservative therapy with a duration of no more than 1 week was administered to stabilize the general condition and control the infection as much as possible before surgery.

Surgical methods

All patients were in the prone position after administration of general endotracheal anesthesia, and a C-arm X-ray was used to confirm the lesion segment. Subperiosteal detachment of the bilateral paraspinal muscles was performed through a posterior midline approach. The spinous process, lamina, transverse processes, and facet joints of the lesion segment and the upper and lower adjacent healthy vertebrae were exposed. Then, pedicle screws were inserted, respectively, at pedicles of the healthy vertebra adjacent to the lesion segment. After the placement of pedicle screws was confirmed by C-arm fluoroscopy, a temporary pre-bent rod referring to the physiological kyphotic angle was installed to avoid spinal cord injury induced by the instability of the spine during decompression and focal debridement. After the extent of vertebral destruction was determined, the posterior structures were removed to achieve complete decompression, and vertebrectomy, including removal of the intervertebral disks, was performed using a combination of a bone chisel and curette rongeur. To clear the surrounding abscess, the caseous tissue and the sequestrum were carefully removed. Moreover, various sizes of curettes were used to achieve full debridement. After decompression, a bone block with a three-sided cortex is cut from the iliac bone, trimmed appropriately, and then implanted into the bone defect area. Alternatively, uncontaminated autologous bone particles collected during surgery are filled into an appropriate titanium mesh cage or n-HA/PA66 cage. The cage is then implanted into the bone defect area. Subsequently, deformity correction and stabilization were ascertained by installing permanent rods. one or two g streptomycin were placed in the intervertebral area during the operation.

Postoperative management

After surgery, temperature, pulse, respiratory rate, and blood pressure were closely monitored and nutritional support and anti-infective treatment were routinely provided. Mobility and sensation of the lower limbs were closely observed. Incision drainage catheter was removed when the drainage volume was less than 30 mL/d. X-ray and CT examination were checked after extubation. Patients were allowed to get out of bed with an appropriate thoracolumbar brace at 2 weeks postoperatively and the brace was applied for at least 3 months postoperatively. After surgery, all patients were asked to continue the same anti-TB drugs that they were taking preoperatively for at least 12 months. Some laboratory examinations including ESR, C-reactive protein (CRP), and hepatic and renal functions were recorded every 3 months to evaluate the efficacy and side effects of the chemotherapeutics. X-ray, CT, and MRI (if necessary) were performed during 3, 6, and 12 months of follow-up.

Outcome indexes

Operative time, operative blood loss, postoperative hospital stay, VAS score, ESR, CRP, and ASIA grade were recorded. Cobb angle (formed by the upper endplate of the upper vertebral body and the lower endplate of the lower vertebral body), the height of the fusion stage (the distance between the upper endplate of the upper vertebral body and the lower endplate of the lower vertebral body), and cage subsidence (the difference between the height of the fusion segment at the last follow up and the height of the fusion segment immediately after surgery) were evaluated during the follow up.

Bone graft fusion time: according to Three-dimensional CT results during the follow-up, the criterion of bone graft fusion reported by Brantigan et al.[14] was used to evaluate whether bone fusion has been achieved. Grade D and Grade E are defined as bone graft fusion in this study.

Statistical analysis

Statistical Package for the Social Sciences (SPSS) 22.0 software (SPSS, Inc., Chicago, IL, USA) was used for statistical analysis. Quantitative data were expressed as mean ± standard deviation. Analysis of variance (ANOVA) and matched t-test were used for intergroup and intragroup comparisons of quantitative data, respectively. Intergroup comparison of disordered qualitative data (e.g., sex, abscess or not) was performed by Chi-square test. Wilcoxon rank-sum test and Mann–Whitney U test were used for intragroup and intergroup comparisons of ordered qualitative data (e.g., ASIA grade), respectively. P < 0.05 was considered to be significant.

  Results 

There were no significant differences in demographic characteristics among the three groups

Fifty-seven patients eligible for inclusion in this study included 13 cases in the iliac bone graft group, 26 cases in the TMC group, and 18 cases in the n-HA/PA66 cage group. No statistically significant differences were found in age (P = 0.857), gender (P = 0.319), and paravertebral abscess (P = 0.376) among the three groups. Comparisons of preoperative demographics among the three groups of patients are shown in [Table 1].

VAS score, ESR, and CRP in each group were significantly improved compared with the values before operation

VAS score, ESR, and CRP were noticeably improved at the time of the last follow-up test compared with the preoperative levels in each group (P < 0.05), but there were no significant differences among the three groups (P = 0.058) [Figure 1]. There were no significant differences in operation time (P = 0.138), surgical blood loss (P = 0.378), and hospitalization stay (P = 0.589) among the three bone graft methods. Comparisons of clinical outcomes among the three groups are shown in [Table 2].

Figure 1: Comparison of operative time (a), operative blood loss (b), hospitalization stay (c), VAS score (d), ESR (e), and CRP (f) among the three groups (#intergroup comparison, P < 0.05; *intragroup comparison, compared with preoperative values, P < 0.05) CRP = C-reactive protein, ESR = erythrocyte sedimentation rate, n-HA/PA66 = nanohydroxyapatite/polyamide-66, VAS = visual analog scale

Click here to view

The Cobb angle in each group was significantly improved compared with the value before operation

The Cobb angle was significantly corrected in all three groups during the last follow up, compared with the preoperative values. But no significant differences were found among preoperative, postoperative, and last follow-up Cobb angles among the three groups. Comparisons of preoperative imaging outcomes among the three groups are shown in [Table 3].

Table 3: Comparison of preoperative imaging outcomes among the three groups

Click here to view

The n-HA/PA66 cage had a faster bone graft fusion time and lower cage subsidence

It is worth noting that the bone graft fusion time of the n-HA/PA66 cage group (4.7 ± 1.8 months) was shorter than the iliac bone graft group (6.3 ± 3.0 months) and the TMC group (6.8 ± 2.6 months) (P < 0.05), and the cage subsidence of the n-HA/PA66 cage group (0.5 ± 0.2 mm) was lower than the iliac bone graft group (1.3 ± 0.3 mm) and the TMC group (1.2 ± 0.5 mm) (P = 0.013) [Figure 2]. Comparisons of the preoperative imaging outcomes among the three groups are shown in [Table 3].

Figure 2: Comparison of follow-up time and bone fusion time (G) among the three groups (*intergroup comparison, compared with preoperative values, P < 0.05). n-HA/PA66 = nanohydroxyapatite/polyamide-66

Click here to view

Neurological function achieved great improvement among the three groups

In the iliac bone graft group, the preoperative ASIA grade changed from grade B to grade D in one case, from grade C to grade E in one case, and from grade D to grade E in one case. In the TMC group, ASIA grade changed from grade C to grade D in one case, from grade C to grade E in two cases, and from grade D to grade E in six cases. In the n-HA/PA66 cage group, ASIA grade changed from grade B to grade D in one case, from grade C to grade D in two cases, and from grade D to grade E in four cases. Patients with ASIA of grade B/C improved with one or two grades at the end of follow-up.

There was no difference in complications among the three groups

In the iliac bone graft group, eight cases had complications including five cases of donor-site pain, one case of superficial wound infection, and two cases of pulmonary infection. In the TMC group, seven cases had complications including one case of liver function damage, one case of superficial wound infection, four cases of pulmonary infection, and one case of urinary tract infection. There were five cases of postoperative complications in the n-HA/PA66 group, including one case of liver function damage, two cases of pulmonary infection, and two cases of superficial wound infection. Chi-square test showed that no significant difference was found in postoperative complications among the three groups. Neurologic deterioration and implant loosening were not observed during the follow-up period. All the complications recovered after active treatment. Changes in ASIA classification preoperatively and at the last follow-up are shown in [Table 4].

Table 4: Changes in ASIA classification preoperatively and at the last follow-up among the three groups

Click here to view

Typical data

Typical cases are presented in [Figure 3], [Figure 4], [Figure 5].

Figure 3: A 50-year-old male with L2–3 STB in iliac bone graft group. (a–c) Preoperative MRI and X-ray showed that L2 and L3 vertebral body and the intervertebral disk were destroyed. (d and e) Postoperative X-ray. (f and g) Postoperative CT. (h) CT at 12 months postoperatively showed bone fusion between L2 and L3. (i and j) X-ray at 12 months showed good location of the posterior instrument. (k and l) X-ray at 39 months postoperatively showed good location of the posterior instrument. CT = computed tomography, MRI = magnetic resonance imaging, STB = spinal tuberculosis

Click here to view

Figure 4: A 50-year-old male with T9–T10 STB in n-HA/PA66 cage group. (a and f) Preoperative CT and MRI showed that T9 and T10 vertebral body and the intervertebral disk were destroyed. (g and h) Postoperative X-ray. (i and j) X-ray at 3 months postoperatively. (k and l) CT at 3 months postoperatively showed bone fusion between T8 and T11. (m and n) CT at 6 months postoperatively. (o and p) X-ray at 18 months postoperatively showed good location of n-HA/PA66 cage and posterior instrument. CT = computed tomography, MRI = magnetic resonance imaging, n-HA/PA66 = nanohydroxyapatite/polyamide-66, STB = spinal tuberculosis

Click here to view

Figure 5: A 51-year-old male with T7–8 STB in titanium mesh bone graft group. (a and d) Preoperative CT and MRI showed that T7 and T8 vertebral body and the intervertebral disk were destroyed. (e and f) Preoperative X-ray. (g and h) Postoperative X-ray. (i) Postoperative CT showed good location of titanium mesh and posterior instrument. (j) CT at 12 months postoperatively showed bone fusion between T6 and T8. (k and l) X-ray at 15 months postoperatively showed good location of titanium mesh and posterior instrument. CT = computed tomography, MRI = magnetic resonance imaging, n-HA/PA66 = nanohydroxyapatite/polyamide-66, STB = spinal tuberculosis

Click here to view

  Discussion 

Treatment of TB should follow the principles of early, appropriate, regular, combined, and whole course. Effective anti-TB chemotherapy is the only guaranteed mainstay treatment, whereas surgical treatment is reserved for the patients who have severe nerve impairment, spinal instability,[15],[39] and progressive kyphosis. Complete removal of lesions is the key to surgical treatment of thoracic and lumbar TB. However, bone defects left by the complete removal of lesions need to be repaired by bone grafting in order to reconstruct the biomechanical line of the spine and achieve early bone fusion. STB often destroys the spinal anterior column and the middle column, and thereby results in instability. Reconstruction of spinal stability is beneficial to alleviate symptoms and to avoid recurrence of TB. According to the three-columns theory of Denis,[16] it is important to integrate the anterior column and the middle column for the reconstruction of spinal stability. At present, the primary methods of reconstruction include the iliac crest, TMC, and new bone graft materials such as the n-HA/PA66 cage. The autogenous iliac crest has long been considered the gold standard for bone graft with good osteoconduction, bone formability, and osteoinductive activity. When tricortical autogenous iliac bone struts are used for grafting, the size and shape of the strut are difficult to estimate before it is removed from the iliac crest and it is also influenced by the experience of the surgeon. Therefore, it has a relatively small weight-bearing contact area and it is mechanically weak, and osteoporosis of the vertebrae and bone graft may lead to discrete loss of height from a fused motion segment.[6] In addition, it has been reported in some literature that the iliac bone strut has some disadvantages such as insufficient strength to maintain axial distension, local microfractures, donor-site morbidities, inadequate bone grafting, and insufficient absorption. The TMC is a representative metal cage device that has been widely used since it was first introduced about 40 years ago.[17] The previous results of using TMC were favorable. The size of TMC is designed by the bone defect, which can maximize the filling defect, and the cross section of TMC can provide the contact area with bone surfaces. Although the high rate of TMC fusion was encouraging, the same high rate of cage subsidence reported by many authors could not be ignored.[18],[19],[20],[21],[22] The hollow cylindrical n-HA/PA66 cage is a novel biomimetic non-metallic cage device combining the strength properties of hydroxyapatite (HA) with the elasticity properties of PA66, which is close to the inherent attributes of human bone. The toughness and strength of n-HA/PA66 materials depend mainly on the homogeneous distribution of n-HA granules in the PA66 matrix. The n-HA/PA66 cage has an appropriate elastic modulus dispersing the stress distribution of the contact surface. Each n-HA/PA66 cage has wide rims, nearly 3 mm,[12] with several shallow recesses designed to prevent subsidence and migration by decreasing the cutting action and increasing the friction between the cage edges with vertebral endplates. The n-HA/PA66 cage had been widely used as a bionic non-metallic bone implant material in STB surgery during the past decades.[23] In this study, no significant difference was found in operative time and blood loss among the three groups. At the last follow-up, VAS score, ESR, CRP, and neurological function were all significantly improved in the three groups due to the effective anti TB chemotherapy and decompression of the spinal canal.[24] A study by Ou et al.[25] on the use of the n-HA/PA66 cage in thoracolumbar surgery reported a fusion rate of 100%, with nearly no loss of height correction in 42 patients with an average 13-month follow-up. The follow-up time of these 42 patients was not long, and pseudarthrosis or larger loss of correction may occur in the future. In a study by Yang et al.,[12] the authors reported a bony fusion rate of over 90% in using n-HA/PA66 cage. Zhao et al.[26] showed an over 90% bony fusion rate and a less than 3% cage subsidence rate in their 35 patients who had an n-HA/PA66 cage fusion. All these studies indicate that the n-HA/PA66 cage is a promising device in STB surgery. In our study, we discovered that bony fusion occurred sooner in patients with n-HA/PA66 cage than with TMC and tricortical autogenous iliac bone. According to Greer,[27] the bone will grow in response to applied stress and will be reabsorbed when lacking mechanical stimulus. The Young's moduli of the TMC and autogenous iliac bone were markedly higher than that of the bone graft inside the cage, whereas the Young's modulus of the n HA/PA66 cage was much lower than that of bone graft.[12] Theoretically,[28] the n-HA/PA66 cage can enable interaction of Ca2+ and PO43− between the cage and surrounding tissue and form a crystal layer on the cage surface.[29] This layer will become a bone bridge assisting in the growth of bone graft. The n-HA/PA66 cage has wider edges, which increase the load-bearing area between the cage and endplate to achieve mechanical stability, ensuring sufficient and uniform compressive stress that facilitates bone fusion.[5] The design of dentation located in the upper and lower end faces helps effectively fix the strut in the initial position with posterior internal fixation, which greatly reduces displacement of the cage. There are many small holes on the surface of the cylinder, which is conducive to the crawling and growing of the capillaries, to facilitate bone fusion.

Local pain, neurovascular injury, local hematoma, infection, and abnormal gait at the iliac donor site[30] pose significant challenges to postoperative outcomes and patient satisfaction. Our study, we found no differences in Cobb angle correction among the three groups. The reason is that the posterior internal fixation system plays an important role in Cobb angle correction, instead of the support of the anterior column.[7] Moreover, the degree of osteoporosis and improper management of endplate during surgery cannot be eliminated, which can influence the correction of Cobb angle. The collapse and displacement of the iliac bone or the subsidence of the cage may also cause Cobb angle loss.[8],[10],[20],[22] All three reconstruction ways require careful handling of the bone graft bed but at the cost of potentially creating bone defects, which may affect the spine's stability and result in limited Cobb angle correction.[7],[26] The difference in the length of the posterior fixation segment may also affect local stability and Cobb angle correction.[4],[12] It is extremely difficult to achieve subchondral resection during surgery. Once the bony endplate is destroyed, the Cobb angle loss is prone to happen.

  Conclusions 

We consider that the three reconstruction methods in the surgery of thoracic and lumbar TB are safe and effective. Great advantages such as lower cage subsidence, higher rate of bone fusion, and fewer complications were observed in our study using n-HA/PA66 cage as the bone graft strut. However, this study has some limitations. Firstly, this study is a retrospective study. Secondly, our sample size for this study is small. Thirdly, we lack data on long-term follow-up. In conclusion, these three reconstruction methods, including iliac bone graft, titanium mesh bone graft, and n-HA/PA66 cage bone graft, can obtain satisfactory clinical results in restoring the ability of the spine and alleviating pain via one-stage posterior debridement, bone graft, and internal fixation, but n-HA/PA66 cage bone graft material can result in lower cage subsidence and a faster time of bone graft fusion.

List of abbreviations

VAS = visual analog scale; ESR = erythrocyte sedimentation rate; CRP = C-reactive protein; ASIA = American Spinal Injury Association; n-HA/PA66 cage = nanohydroxyapatite/polyamide-66 cage; TB = tuberculosis; STB = spinal tuberculosis; TMC = titanium mesh cage; CT = computed tomography; MRI = magnetic resonance imaging.

Ethics approval and consent to participate

The study was approved by the Institutional Review Board of the Second Affiliated Hospital of Chongqing Medical University. Informed consent was obtained from all the participants.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 

  References 
1.Jain AK. Tuberculosis of the spine: A fresh look at an old disease. J Bone Joint Surg Br 2010;92:905-13.  
    2.Jain AK, Rajasekaran S, Jaggi KR, Myneedu VP. Tuberculosis of the Spine. J Bone Joint Surg Am 2020;102:617-28.  
    3.Dunn RN, Ben Husien M. Spinal tuberculosis: Review of current management. Bone Joint J 2018;100-B: 425-31.  
    4.Ran B, Xie YL, Yan L, Cai L. One-stage surgical treatment for thoracic and lumbar Spinal tuberculosis by transpedicular fixation, debridement, and combined interbody and posterior fusion via a posterior-only approach. J Huazhong Univ Sci Technolog Med Sci 2016;36:541-7.  
    5.Assaghir YM, Refae HH, Alam-Eddin M. Anterior versus posterior debridement fusion for single-level dorsal tuberculosis: The role of graft-type and level of fixation on determining the outcome. Eur Spine J 2016;25:3884-93.  
    6.Rajasekaran S. Kyphotic deformity in spinal tuberculosis and its management. Int Orthop 2012;36:359-65.  
    7.Yin XH, Liu ZK, Hao D. The reasons and clinical treatments of postoperative relapse of Pott's disease. Medicine (Baltimore) 2018;97:e12471.  
    8.Du X, Ou YS, Xu S, He B, Luo W, Jiang DM. Comparison of three different bone graft methods for single segment lumbar tuberculosis: A retrospective single-center cohort study. Int J Surg 2020;79:95-102.  
    9.Myhre AP, Jarosz TJ, Hunter JC, Richardson ML. Postoperative bone graft displacement: An unusual sign of infection following posterior spinal fusion. Radiol Case Rep 2015;1:21-3.  
    10.Siddiqui AA, Jackowski A. Cage versus tricortical graft for cervical interbody fusion. A prospective randomised study. J Bone Joint Surg Br 2003;85:1019-25.  
    11.García-Gareta E, Coathup MJ, Blunn GW. Osteoinduction of bone grafting materials for bone repair and regeneration. Bone 2015;81:112-21.  
    12.Yang X, Chen Q, Liu L, Song Y, Kong Q, Zeng J, et al. Comparison of anterior cervical fusion by titanium mesh cage versus nano-hydroxyapatite/polyamide cage following single-level corpectomy. Int Orthop 2013;37:2421-7.  
    13.Huang J, Wei J, Jin S, Zou Q, Li J, Zuo Y, et al. The ultralong-term comparison of osteogenic behavior of three scaffolds with different matrices and degradability between one and two years. J Mater Chem B 2020;8:9524-32.  
    14.Brantigan JW, Steffee AD. A carbon fiber implant to aid interbody lumbar fusion. Two-year clinical results in the first 26 patients. Spine (Phila Pa 1976). 1993;18:2106-7.  
    15.Guerado E, Cerván AM. Surgical treatment of spondylodiscitis. An update. Int Orthop 2012;36:413-20.  
    16.Denis F. The three column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine (Phila Pa 1976) 1983;8:817-31.  
    17.Riew KD, Rhee JM. The use of titanium mesh cages in the cervical spine. Clin Orthop Relat Res 2002:47-54. doi: 10.1097/00003086-200201000-00006.  
    18.Zhang HQ, Li M, Wang YX. Minimum 5-year follow-up outcomes for comparison between titanium mesh cage and allogeneic bone graft to reconstruct anterior column through posterior approach for the surgical treatment of thoracolumbar spinal tuberculosis with kyphosis. World Neurosurg 2019;127:e407-e15.  
    19.Zhang H, Sheng B, Tang M. One-stage surgical treatment for upper thoracic spinal tuberculosis by internal fixation, debridement, and combined interbody and posterior fusion via posterior-only approach. Eur Spine J 2013;22:616-23.  
    20.Yin XH, Liu ZK, He BR, Hao DJ. Single posterior surgical management for lumbosacral tuberculosis: Titanium mesh versus iliac bone graft: A retrospective case-control study. Medicine (Baltimore) 2017;96:e9449.  
    21.Wang YX, Zhang HQ, Li M, Tang MX, Guo CF, Deng A, et al. Debridement, interbody graft using titanium mesh cages, posterior instrumentation and fusion in the surgical treatment of multilevel noncontiguous spinal tuberculosis in elderly patients via a posterior-only. Injury 2017;48:378-83.  
    22.Chen Y, Chen D, Guo Y. Subsidence of titanium mesh cage: A study based on 300 cases. J Spinal Disord Tech 2008;21:489-92.  
    23.Liu JM, Chen XY, Zhou Y. Is nonstructural bone graft useful in surgical treatment of lumbar spinal tuberculosis?: A retrospective case-control study. Medicine (Baltimore) 2016;95:e4677.  
    24.Yao Y, Zhang H, Liu M. Prognostic factors for recovery of patients after surgery for thoracic spinal tuberculosis. World Neurosurg 2017;105:327-31.  
    25.Ou Y, Jiang D, Quan Z, An H, Liu B. Application of artificial vertebral body of biomimetic nano-hydroxyapatite/polyamide 66 composite in anterior surgical treatment of thoracolumbar fractures. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi 2007;21:1084-8.  
    26.Zhao Z, Jiang D, Ou Y, Tang K, Luo X, Quan Z. A hollow cylindrical nano-hydroxyapatite/polyamide composite strut for cervical reconstruction after cervical corpectomy. J Clin Neurosci 2012;19:536-40.  
    27.Greer RB 3rd. Wolff's Law. Orthop Rev 1993;22:1087-8.  
    28.Qiao B, Li J, Zhu Q. Bone plate composed of a ternary nano-hydroxyapatite/polyamide 66/glass fiber composite: Biomechanical properties and biocompatibility. Int J Nanomedicine 2014;9:1423-32.  
    29.Xu Q, Lu H, Zhang J, Lu G, Deng Z, Mo A. Tissue engineering scaffold material of porous nanohydroxyapatite/polyamide 66. Int J Nanomedicine 2010;5:331-5.  
    30.Ebraheim NA, Elgafy H, Xu R. Bone-graft harvesting from iliac and fibular donor sites: Techniques and complications. J Am Acad Orthop Surg 2001;9:210-8.  
    31.Goyal N, Ahuja K, Yadav G, Gupta T, Ifthekar S, Kandwal P. PEEK vs Titanium Cage for Anterior Column Reconstruction in Active Spinal Tuberculosis: A Comparative Study. Neurol India 2021;69:966-72.  
[PUBMED]  [Full text]  32.Uniyal R, Garg RK, Pandey S, Kumar N, Malhotra HS. Mediastinal Widening in a Patient with Paraplegia: An Unusual Cause. Neurol India 2020;68:1201-2.  
[PUBMED]  [Full text]  33.Kim HS, Wu PH, Raorane HD, Jang IT. Generation Change of Practice in Spinal Surgery: Can Endoscopic Spine Surgery Expand its Indications to Fill in the Role of Conventional Open Spine Surgery in Most of Degenerative Spinal Diseases and Disc Herniations: A Study of 616 Spinal Cases 3 Years. Neurol India 2020;68:1157-65.  
[PUBMED]  [Full text]  34.Amitkumar M, Singh PK, Singh KJ, Khumukcham T, Sawarkar DP, Chandra SP, et al. Surgical Outcome in Spinal Operation in Patients Aged 70 Years and Above. Neurol India 2020;68:45-51.  
[PUBMED]  [Full text]  35.Yerramneni VK, Kanala RR, Kolpakawar S, Yerragunta T. MITLIF Operative Nuances- Step by Step. Neurol India 2021;69:1196-9.  
[PUBMED]  [Full text]  36.Zhu C, Huang S, Song Y, Liu H, Liu L, Yang X, et al. Surgical Treatment of Scoliosis-Associated with Syringomyelia: The Role of Syrinx Size. Neurol India 2020;68:299-304.  
[PUBMED]  [Full text]  37.Grasso G, Paolini S, Sallì M, Torregrossa F. Lumbar Spinal Fixation Removal by a Minimal Invasive Microscope-Assisted Technique. Case Report with Technical Description. Neurol India 2020;68:1211-3.  
[