Kee-Yong Ha

Posterior Instrumentation and Anterior Interbody Fusion for Tuberculous Kyphosis of Dorsal and Lumbar Spines

Study Design Thirty-nine adults and five children with active spinal tuberculosis and resulting kyphosis of the dorsal and lumbar spine who had combined posterior instrumentation and anterior interbody fusion were observed to determine whether the corrected spinal deformity could be maintained until solid fusion. Objective To evaluate the effectiveness of the combined two-stage procedure for treating kyphosis due to active spinal tuberculosis. Summary of Background Data Until 1970, with all methods of treatment, kyphosis due to active spinal tuberculosis tended to increase during therapy. Most of the patients treated with these methods were not happy with this residual kyphosis, even though their disease was arrested or cured. Kyphosis became their main concern regarding further treatment. Methods A combined two-stage procedure, under the cover of 18 months of triple chemotherapy, was used for all patients. For posterior stabilization, the Harrington distraction system, Rush nails or Steinmann pins and wires, and Texas Scottish Rite Hospital instrumentation were used. The diagnosis of successful inter-body fusion was made if there was no loss of correction, no graft resorption or graft bed resorption, and if there was visible graft remodeling, such as trabeculation between the graft beds and graft and the graft hypertrophy. Results In the 39 adults, average preoperative, immediate postoperative, and last follow-up kyphosis angles were 37°, 16°, and 18°, respectively. In four children, the average preoperative, immediate postoperative, and last follow-up kyphosis angles were 55° 28°, and 31°, respectively. The loss of correction did not exceed 3°. For one-segment spondylodesis, the average fusion times were 4 months in adults and 3.5 months in children. For a two-segment fusion, the average fusion times were 6 months in adults and 6.3 months in children. Conclusion Posterior instrumental stabilization and anterior interbody fusion were found helpful in arresting the disease early, providing early fusion, preventing progression of kyphosis, and correcting the kyphosis.

Adherence and Biofilm Formation of Staphylococcus Epidermidis and Mycobacterium Tuberculosis on Various Spinal Implants

Study Design. Bacterial adherence and biofilm formation in implant-associated infection may vary depending on species of microorganisms and characteristics of implant surfaces. Objectives. We evaluated the differences in adherence and biofilm formation between Staphylococcus epidermidis and Mycobacterium tuberculosis on various spinal implant surfaces. Summary of Background Data. In implant-associated infections, bacteria in biofilm are resistant to antibiotics or host defense mechanism. The removal of implants is usually necessary to eradicate infection. On the contrary, in tuberculous infection, complete debridement and antituberculous chemotherapy without removal of implant have been regarded as a safe procedure. Methods. S. epidermidis and M. tuberculosis were cultured with 4 types of metal segments, smooth or rough-surfaced stainless steel, and titanium alloy, respectively. After isolation of colonized microorganisms and biofilm with trypsin treatment and culture on plate media, colony-forming units were counted. The features of adherence and biofilm formation were observed under scanning electron microscopy. Results. Biofilm-forming S. epidermidis showed heavy adhesion and multiplication on the surface of all 4 metal segments, 16.5 times more colony-forming units than nonbiofilm-forming ones. On scanning electron microscopy, there were many aggregated microcolonies with thick biofilm in biofilm-forming S. epidermidis but much less in nonbiofilm-forming S. epidermidis. M. tuberculosis were rarely adhered to metal surfaces and showed scanty biofilm formation. Conclusions. On the contrary to S. epidermidis, adherence and biofilm formation of M. tuberculosis on implant surface are less likely, and it can provide the basis of successful instrumentation in spine tuberculosis.

Degeneration of Sacroiliac Joint After Instrumented Lumbar or Lumbosacral Fusion : A Prospective Cohort Study Over Five-Year Follow-up

Study Design. A prospective cohort study. Objective. To determine the cause-effect relationship between fusion and sacroiliac joint (SIJ) degeneration after instrumented posterolateral lumbar or lumbosacral fusion. Summary of Background Data. Adjacent segment degeneration following spinal fusion has attracted considerable attention. However, little attention has been paid to the SIJ, which is one of the adjacent joints. Methods. This study prospectively examined 37 patients, who underwent instrumented posterolateral lumbar/lumbosacral fusion from July 1997 to October 1998. Among them, 32 patients were included in this study and defined as the fusion group (male/female: 10/22, mean age: 64 years). The fusion group was divided into 2 subgroups according to the range of fusion. Group 1 had floating fusion (fusion to L5) and included 22 patients (male/female: 7/15, mean age: 65.6 years). Group 2 had fixed fusion (fusion to S1) and included 10 patients (male/female: 3/7, mean age: 60.5 years). Thirty-four age-matched normal individuals (male/female: 18/16, mean age: 64.5 years) were recruited as a control group. SIJ degeneration was assessed by confirming the absence of degeneration in the SIJ by computed tomography scans before surgery and 2 weeks after surgery. The SIJ was evaluated again by taking computed tomography scans at 1 year and 5 years after surgery. The incidence of SIJ degeneration was evaluated and compared (fusion group vs. control group; group 1 vs. group 2). The clinical outcomes were evaluated using the Visual Analog Scales (VAS) and Oswestry Disability Index (ODI) before surgery and at the final follow-up. Results. The incidence of SIJ degeneration in the fusion group was 75% (24/32), which was significantly higher than that of the control Group 38.2% (13/34) (P < 0.05). The incidence of SIJ degeneration (bilateral and unilateral) and bilateral SIJ degeneration was higher in group 2 than in group 1 (P = 0.028 and 0.04, respectively). The incidence of SIJ degeneration was not associated with the number of fusion segments. At the 5-year follow-up, the patients in groups 1 and 2 reported significant improvements in the VAS and ODI scores compared withthe preoperative scores. However, there was no significant difference in the decrease in VAS and ODI scores between the 2 groups (P = 0.145 and 0.278, respectively). Conclusion. Instrumented posterolateral lumbar/lumbosacral fusion can be a cause of SIJ degeneration. SIJ degeneration develops more often in patients undergoing lumbosacral fusion regardless of the number of fusion segments.

Senescence mechanisms of nucleus pulposus chondrocytes in human intervertebral discs

BACKGROUND CONTEXT The population of senescent disc cells has been shown to increase in degenerated or herniated discs. However, the mechanism and signaling pathway involved in the senescence of nucleus pulposus (NP) chondrocytes are unknown. PURPOSE To demonstrate the mechanisms involved in the senescence of NP chondrocytes. STUDY DESIGN/SETTING Senescence-related markers were assessed in the surgically obtained human NP specimens. PATIENT SAMPLE NP specimens remaining in the central region of the intervertebral disc were obtained from 25 patients (mean: 49 years, range: 20-75 years) undergoing discectomy. Based on the preoperative magnetic resonance images, there were 3 patients with Grade II degeneration, 17 patients with Grade III degeneration, and 5 patients with Grade IV degeneration. OUTCOME MEASURES We examined cell senescence markers (senescence-associated beta-galactosidase [SA-beta-gal], telomere length, telomerase activity, p53, p21, pRB, and p16) and the hydrogen peroxide (H(2)O(2)) content as a marker for an oxidative stress in the human NP specimens. METHODS SA-beta-gal expression, telomere length, telomerase activity, and H(2)O(2) content as well as their relationships with age and degeneration grades were analyzed. For the mechanism involved in the senescence of NP chondrocytes, expressions of p53, p21, pRB, and p16 in these cells were assessed with immunohistochemistry and Western blotting. RESULTS The percentages of SA-beta-gal-positive NP chondrocytes increased with age (r=.82, p<.001), whereas the telomere length and telomerase activity declined (r=-.41, p=.045; r=-.52, p=.008, respectively) However, there was no significant correlation between age and H(2)O(2) contents (p=.18). The NP specimens with Grade III or Grade IV degeneration showed significantly higher percentages of SA-beta-gal-positive NP chondrocytes than those with Grade II degeneration (p=.01 and p=.025, respectively). Immunohistochemistry showed that the senescent NP chondrocytes in all the specimens expressed p53, p21, and pRB, but a few NP chondrocytes in only two specimens expressed p16. Western blotting showed that the expressions of p53, p21, and pRB displayed a corresponding pattern, that is, a strong p53 expression led to strong p21 and pRB expressions and vice versa. CONCLUSIONS Our in vivo study demonstrated that senescent NP chondrocytes increased or accumulated in the NP with increasing age and advancing disc degeneration. The NP chondrocytes in the aging discs exhibited characteristic senescent features such as an increased SA-beta-gal expression, shortened telomeres, and decreased telomerase activity. We further demonstrated that the telomere-based p53-p21-pRB pathway, rather than the stress-based p16-pRB pathway, plays a more important role in the senescence of NP chondrocytes in an in vivo condition. Our results suggest that prevention or reversal of the senescence of NP chondrocytes can be a novel therapeutic target for human disc degeneration.

Expression of estrogen receptor of the facet joints in degenerative spondylolisthesis.

Study Design. Immunohistochemical study was done by harvesting articular cartilage of the facet joints during the decompressive surgery for spinal stenosis. Objectives. To observe the expression of estrogen receptor on the articular cartilage of the facet joints in degenerative spondylolisthesis (DS) Summary of Background Data. Few attempts have been made to evaluate the effect of sex-hormone, although DS is more common in females than in males. Methods. After harvesting the articular cartilage of the facet joints in 17 DS and in 15 spinal stenosis (SS) patients, the expression of estrogen receptor and the severity of facet arthritis were observed by H-E and immunohistochemical staining, respectively. Measurements of both staining were made by using a semiquantitative analysis. Results. The significantly increased expression of estrogen receptor correlated with the severity of facet arthritis (r = 0.78, P < 0.05). There was a significantly increased expression of estrogen receptor of the facet joint in DS compared with SS (P < 0.01). The histologic-histochemical grading of cartilage lesion in DS was 12.4 (SEM, 0.6), which was significantly higher than in SS (P < 0.05). Conclusions. These findings suggest that the higher expression of estrogen receptor might aggravate degenerative change of the facet articular cartilage and might also be considered one of the causative factors for DS in postmenopausal women.

Percutaneous vertebroplasty for vertebral compression fractures with and without intravertebral clefts

We present the clinical and radiological results of percutaneous vertebroplasty in the treatment of 58 vertebral compression fractures in 51 patients at a minimum follow-up of two years. Group 1 consisted of 39 patients, in whom there was no associated intravertebral cleft, whilst group 2 comprised 12 patients with an intravertebral cleft. The Oswestry disability index (ODI) and visual analogue scale (VAS) scores were recorded prospectively. The radiological evidence of kyphotic deformity, vertebral height, leakage of cement and bone resorption around the cement were studied retrospectively, both before and after operation and at the final follow-up. The ODI and VAS scores in both groups decreased after treatment, but the mean score in group 2 was higher than that in group 1 (p = 0.02 (ODI), p = 0.02 (VAS)). There was a greater initial correction of the kyphosis in group 2 than in group 1, although the difference was not statistically significant. However, loss of correction was greater in group 2. Leakage of cement was seen in 24 (41.4%) of 58 vertebrae (group 1, 32.6% (15 of 46); group 2, 75% (9 of 12)), mainly of type B through the basal vertebral vein in group 1 and of type C through the cortical defect in group 2. Resorption of bone around the cement was seen in three vertebrae in group 2 and in one in group 1. There were seven adjacent vertebral fractures in group 1 and one in group 2. Percutaneous vertebroplasty is an effective treatment for osteoporotic compression fractures with or without an intravertebral cleft. Nonetheless, higher rates of complications related to the cement must be recognised in patients in the presence of an intravertebral cleft.

Pott's Paraplegia-67 cases

Sixty-seven patients were treated for Potts paraplegia: 58 were adults and 9 were children. Sixty-four patients had active disease, and 3 had healed disease. All patients had triple chemotherapy with or without decompression surgery. Thirteen patients, including 9 children, were treated conservatively, whereas 54 patients who met the selection criteria for surgery were treated surgically. Fifty-two patients had anterior radical decompression surgery, and for 14 of them, anterior surgery was preceded by posterior instrumental stabilization surgery. Two patients with healed disease had posterior decompressive corpectomy. There was functional recovery in 60 (89.6%) patients, including the 13 who had active disease that was treated conservatively. In 47 of the 54 surgically treated patients there was neurologic recovery, and 2 of these recovered incompletely with some residual spasticity. In the remaining 7 patients, there was no recovery. It took 2 to 6 months for recovery for the patients with conservative treatment, whereas it took <2 months for the patients with anterior decompression. The patients who had the combined 2-stage procedure could be mobilized earlier after neurologic recovery than could the patients having the anterior radical surgery and the conservatively treated patients. It was proven that paraplegia of active disease can be treated successfully by conservative or surgical means and that paraplegia caused by healing of fibrosis in the severely deformed spine was difficult to treat successfully, even with radical surgery.

An autocrine or paracrine Fas-mediated counterattack: a potential mechanism for apoptosis of notochordal cells in intact rat nucleus pulposus.

Study Design. Immunohistochemistry and in situ nick end-labeling (TUNEL) were performed in rat lumbar intervertebral discs. Objectives. To demonstrate the mechanism of notochordal cell death in the nucleus pulposus (NP). Summary of Background Data. With age, notochordal cells gradually disappear in the NP. We hypothesized that this phenomenon might be related to Fas-mediated apoptosis. Materials and Methods. Expressions of Fas; Fas ligand (FasL); caspase 3, 8, 9, 10; Ki-67 protein; and TUNEL were examined in 4-week-, 6-month- and 12-month-old rat NPs. Apoptosis (TUNEL-positive) and proliferation potential (Ki-67-positive) indexes of notochordal cells were calculated and compared among age groups. Results. Notochordal cells constitutively expressed both Fas and FasL. Among their downstream initiator (caspase 8, 9, and 10) and executioner (caspase 3) caspases tested, caspase 9 and 3 were expressed. Proliferation potential of the notochordal cells was the highest at 4 weeks (1.96 ± 1.3%) and decreased to a significantly lower level at 6 (0.81 ± 0.68%) and 12 months (0.8 ± 0.37%; P = 0.03 and 0.01, respectively). In contrast, apoptosis of the notochordal cells was the lowest at 4 weeks (3.52 ± 1.07%) and increased to a significantly higher level at 6 (19.38 ± 10.99%) and 12 months (21.51 ± 16.99%; P < 0.001 in both comparisons). Conclusions. Fas-mediated mitochondrial caspase 9 pathway is constitutively present in the rat notochordal cells. The constitutive expression of Fas, FasL and its downstream caspases, as well as the homogeneity ofnotochordal cell population suggests an autocrine or paracrine Fas-mediated counterattack to be a potential mechanism for apoptosis of rat notochordal cells. A regulated negative balance of notochordal cell proliferation against apoptosis is likely to involve the disappearance of notochordal cells in the rat NP. This information on the mechanism for apoptosis of notochordal cells could be important in the investigation of intervertebral disc development as well as aging and perhaps degeneration.

Comparison of posterolateral fusion with and without additional posterior lumbar interbody fusion for degenerative lumbar spondylolisthesis.

Objectives The surgical approach that should be used for degenerative spondylolisthesis (DS) is a controversial issue. Decompression and posterolateral fusion (PLF) with or without lumbar interbody fusion is widely used. Many studies have compared the outcomes of these 2 approaches, but the appropriate indications for these approaches are still unclear. The authors retrospectively studied the effects of posterior lumbar interbody fusion (PLIF) after PLF for the treatment of DS. Methods Forty patients who underwent single level decompression and posterior instrumentation for DS at L4-5 and were followed for at least 2 years were retrospectively studied. The patients were divided into 4 groups: the stable PLF group (S-PLF, n=13); the stable PLF with additional PLIF group (S-PLIF, n=11); the unstable PLF group (U-PLF, n=8); and the unstable PLF with additional PLIF group (U-PLIF, n=8). Clinical and radiographic comparisons were carried out between the S-PLF and S-PLIF groups, and between the U-PLF and U-PLIF groups. Results Clinical assessments, using the improvements of the Oswestry Disability Index (ODI) and the Visual Analog Scale (VAS), were statistically significantly different between the 2 unstable groups (ΔU-PLF <ΔU-PLIF, P(ODI)=0.032, P(VAS)=0.004, respectively). On radiologic assessment, the slip angle increment was significantly different between the 2 stable groups (ΔS-PLF>ΔS-PLIF, P=0.029), and the disc height increment was significantly different between the 2 stable groups (ΔS-PLF<ΔS-PLIF, P=0.043) and between the 2 unstable groups (ΔU-PLF<ΔU-PLIF, P=0.042). Conclusions This study suggests that preoperative segmental instability may be a criterion determining whether an additional PLIF would be beneficial in the treatment of lumbar DS.

The fate of anterior autogenous bone graft after anterior radical surgery with or without posterior instrumentation in the treatment of pyogenic lumbar spondylodiscitis.

Study Design. A retrospective clinical study. Objective. To assess the results of anterior strut grafting and the loss of the reduction in anterior interbody fusion and anterior interbody fusion combined with posterior instrumental fusion in pyogenic spondylodiscitis. Summary of Background Data. Resorption of the anterior graft is an ominous sign following most anterior surgery. Thus, additional posterior instrumentation has been used to prevent collapse of the anterior graft. However, its effect is controversial, and few studies have examined the fate of the anterior strut graft. Methods. Twenty-four consecutive patients underwent surgical treatment for pyogenic spondylodiscitis. The patients were divided into Group I (anterior interbody fusion) and Group II (anterior interbody fusion + posterior instrumented fusion). The sagittal angle, intervertebral height, and complications relating to the anterior graft were compared. Results. Solid bone fusion was achieved in 23 (95.8%) patients. The sagittal angle and the intervertebral height were similar in Groups I and II (P = 0.61, P = 0.89, respectively). In Groups I and II, the postoperative sagittal angle was maintained until 1 month after surgery (P > 0.05), but it decreased significantly by 3 months after surgery (P < 0.05). In Groups I and II, intervertebral height correction was maintained until 1 month after surgery (P > 0.05), but by 3 months after surgery, it had collapsed significantly (P < 0.05). Subsidence of the graft occurred through the damaged endplate. Group I included 1 case of graft dislodgement necessitating revision; there were no such cases in Group II. There were no recurrences of infection in either group. Conclusion. Reduction of intervertebral height and loss of sagittal profile occurred in both groups. Complications relating to the bone graft were more common in Group I than in Group II. Despite loss of correction, both groups had a high fusion rate without recurrence of infection. The reduction of intervertebral graft height appears to be the result of destruction of the endplate either due to surgical debridement or the infective process.