Effect of adjacent segmental facet joint degeneration on adjacent segment disease after lumbar fusion and fixation / 中国骨伤

OBJECTIVE@#To explore the effect of facet joint degeneration in adjacent segments on the incidence of adjacent segment disease (ASD) after lumbar fusion and fixation.@*METHODS@#A retrospective analysis was performed on 138 patients who underwent L5S1 posterior lumbar interbody fusion (PLIF) from June 2016 to June 2019. Patients were divided into a degeneration group (68 cases) and a non-degenerative group (70 cases) based on the presence or absence of L4,5 facet joint degeneration before surgery (graded using the Weishaupt standard). Age, gender, body mass index (BMI), follow-up time, and preoperative L4,5 intervertebral disc degeneration (graded using the Pfirrmann standard) were collected for both groups. Clinical outcomes were evaluated using the visual analogue scale (VAS) and Oswestry disability index (ODI) at 1 and 3 months after surgery. The incidence and time of ASD after surgery were analyzed.@*RESULTS@#There were no significant differences between the two groups in age, gender, BMI, follow-up time, or preoperative L4,5 intervertebral disc degeneration. Both groups showed significant improvement in VAS and ODI at 1 and 3 months after surgery (P<0.001), with no significant difference between the groups(P>0.05). However, there was a statistically significant difference in the incidence and timing of ASD between the groups (P<0.05). The degeneration group had 2 cases of ASD in gradeⅠdegeneration, 4 cases of ASD in gradeⅡdegeneration, and 7 cases of ASD in grade Ⅲ degeneration. There was a statistically significant difference between the number of patients with grade Ⅲ degeneration and those with gradesⅠandⅡASD (P<0.0167, Bonferroni correction).@*CONCLUSION@#Preoperative degeneration of adjacent articular processes will increase the risk of ASD after lumbar fusion fixation, whereas gradeⅢ degeneration will further increase the risk.

Oblique lateral interbody fusion treats adjacent segment diseases after lumbar spinal fusion / 中华骨科杂志

Objective:To explore the feasibility and clinical efficacy of oblique lateral interbody fusion (OLIF) in the treatment of adjacent segment disease (ASDis).Methods:Retrospective analysis was conducted on the data of 31 patients with ASDis treated by OLIF in four medical centers from June 2015 to December 2018. There were 17 males and 14 females. The average age was (65.7±3.4) years (range, 59 to 75 years). 19 cases received single-segment fixed fusion, 11 cases received double-segment fixed fusion and 1 case received three-segment fixed fusion. Original fixed fusion site: 1 case of L 1, 2, 3 cases of L 3, 4, 11 cases of L 4, 5, 4 cases of L 5S 1, 6 cases of L 3-L 5, 5 cases of L 4-S 1, and 1 case of L 3-S 1. The time from the initial fixation and fusion to this admission was 82.5±45.5 months (rang, 24 to 180 months). ASDis occurred at the proximal end of the fixed fusion segment in 28 cases and at the distal end in 3 cases. The types of ASDis: degenerative disc disease in 11 cases, lumbar spinal stenosis in 15 cases, degenerative spondylolisthesis in 2 cases, and degenerative scoliosis in 3 cases. The location of ASDis: 6 cases of L 2, 3, 12 cases of L 3, 4, 6 cases of L 4, 5, 3 cases of L 1-L 3, 1 case of L 2-L 4, and 3 cases of L 1-L 4. At admission, 3 cases of lumbar internal fixation had been removed and 28 cases of internal fixation remained. Stand-alone OLIF was performed in 19 cases, OLIF combined with pedicle screw fixation in 8 cases, and OLIF combined with cortical screw fixation in 4 cases. Visual analogue scale (VAS) and Oswestry disability index (ODI) were used to evaluate the low back pain and lumbar function before operation and at the last follow-up, and the imaging results and complications were observed. Results:All patients were followed up. The follow-up time was 23.6±9.6 months (range, 12 to 60 months). The operation time was 73.8±25.3 mins (range, 40 to 180 min), and the intraoperative blood loss was 86.2±67.4 ml (range, 20 to 310 ml). The average blood loss in each segment was 24.8 ml. During the operation, there were 1 case of segmental vein injury, 7 cases of endplate injury, 2 cases of transient iliopsoas muscle weakness, 1 case of thigh pain and numbness, and 1 case of incomplete intestinal obstruction. There was no incision necrosis and infection. The VAS score of low back pain decreased from 5.9±1.9 before operation to 1.4±0.6 at the last follow-up, with a statistically significant difference ( t=8.47, P<0.001). The ODI index recovered from 45.2%±5.7% before operation to 13.8%±4.7% at the last follow-up, with a statistically significant difference ( t=7.92, P<0.001). The height of intervertebral space increased from 8.7±1.6 mm before operation to 11.4±1.9 mm after operation and 9.9±1.8 mm at the last follow-up. There was a statistically significant difference between postoperative and preoperative height of intervertebral space ( F=4.15, P=0.007). There was a statistically significant difference between the last follow-up and postoperative height of intervertebral space ( P=0.011). During the follow-up, there were 13 cases of fusion cage subsidence, 1 case of fusion cage displacement, and no case of internal fixation loosening or fracture. The intervertebral fusion rate was 94%(29/31) and the complication rate was 42%(13/31). Conclusion:ASDis is a common complication after lumbar fixation and fusion, and requires surgical treatment. OLIF is a reliable method to treat ASDis as it has advantages of small trauma, high fusion rate and low complication rate.

Correlation between spinopelvic sagittal parameters and adjacent segment disease after lumbar fusion / 第二军医大学学报

Objective To analyze the correlation between adjacent segment disease (ASDis) after lumbar fusion and spinopelvic sagittal parameters, and to explore the risk factors. Methods From Jan. 2013 to Oct. 2017, the patients undergoing revision surgery for ASDis after lumbar fusion in Changhai Hospital of Naval Medical University (Second Military Medical University) were enrolled as ASDis group, and the patients who did not have ASDis after lumbar fusion during the same follow-up period were taken as controls. The clinical data of the patients in the two groups were retrospectively analyzed. The differences of the general data (age, gender, body mass index [BMI], follow-up time and the etiology of the first operation) and the spinopelvic sagittal parameters (thoracic kyphosis [TK], sagittal vertical axis [SVA], lumbar lordosis [LL], segmental lumbar lordosis [sLL], pelvic incidence [PI], pelvic tilt [PT] and sacral slope [SS]) were compared between the two groups. Results There were 25 patients in the ASDis group and 50 patients in the control group. There were no significant differences in the age, gender, BMI, follow-up time or the etiology of the first operation between the two groups (all P>0.05). Compared with the control group, the LL, sLL and SS were significantly lower in the ASDis group (36.00°±5.44°vs 43.88°±10.62°, 17.80°±5.79°vs 27.62°±6.74°, 27.50°±5.30°vs 31.06°±7.48° all P0.05). Meantime, the proportion of patients with SVA>50 mm, the difference of PT and LL (PT-LL)=10°, and the ratio of sLL to LL (RL)<60% were significantly higher in the ASDis group than those in the control group (18/25 vs 21/50, 16/25 vs 11/50, 21/25 vs 17/50; all P<0.05). Conclusion The sagittal imbalance after lumbar fusion is closely associated with ASDis, and compensatory kyphosis of adjacent lumbar segments due to surgical segmental lordosis may be one of the causes of ASDis after lumbar fusion.

Is Adjacent Segment Disease More Frequent in Proximal Levels in Comparison with Distal Levels? Based on Radiological Data of at Least 2 Years Follow Up with More than 2 Level Thoracolumbar Fusions

OBJECTIVE: The purpose of this retrospective study was to determine which of the proximal adjacent segment disease (ASD) and distal ASD was more prevalent and what parameters is more related to ASD in proximal levels and distal levels after more than 2 levels fusions.METHODS: The medical records were reviewed retrospectively for 856 cases. A total of 66 cases of ASD were enrolled. On pre-op magnetic resonance imaging, disc degeneration was measured at the upper and lower parts of surgically treated levels and confirmed by the commonly used Pfirrmann grade. Segmental flexibility in sagittal plane was embodied in segment range of motion (ROM) obtained through flexion and extension X-ray before surgery. Coronal angle was recorded as methods Cobb’s angle including fusion levels preoperatively. For the comparison of categorical variables between two independent groups, the chi-square test and Fisher exact test were performed.RESULTS: Proximal ASD and distal ASD were 37/856 (4.32%) and 29/856 (3.39%), respectively. The incidence of proximal ASD was relatively high but insignificant differences. In comparison between ASD group and non ASD group, proximal Pfirmman was higher in proximal ASD and distal Pfirmman was higher in distal ASD group (p=0.005, p<0.008, respectively). However, in the ROM, proximal ROM was higher in proximal ASD, but distal ROM was not different between the two groups (p<0.0001, p=0.995, respectively). Coronal angle was not quite different in both groups (p=0.846).CONCLUSION: In spite of higher frequency in ASD in proximal level in spinal fusion, it is not clear that incidence of ASD in proximal level is not higher than that of distal ASD group in more than 2 level thoracolumbar fusions. Not only Pfirrmann grade but also proximal segmental ROM is risk factor for predicting the occurrence of ASD in patients more than 2 level of thoracolumbar spine fusion operation excluding L5S1.

Radiologic Comparison of the Sacroiliac Joint Degeneration Following Lumbar or Lumbosacral Fusion / 대한척추외과학회지

STUDY DESIGN: Retrospective study.OBJECTIVES: To compare the degeneration of sacroiliac joint (SIJ) following lumbar or lumbosacral fusion.SUMMARY OF LITERATURE REVIEW: The SIJ is adjacent to lumbosacral junction and its degeneration can be the potential cause of pain. However, the study addressing SIJ degeneration following lumbar or lumbosacral fusion is very limited.MATERIALS AND METHODS: From June 2002 to June 2012, 98 patients who underwent posterior decompression and posterolateral fusion were included in this study. The study group was divided into 2 groups according to the range of fusion. Group A had fusion to L5 and included 34 patients. Group B had fusion to S1 and included 64 patients. We evaluated the five years postoperative radiologic and clinical outcomes retrospectively.RESULTS: There was no statistically significant difference of bilateral preoperative subchondral sclerosis and osteophytes of the SIJ between group A and group B. However, group B revealed statistically significant subchondral sclerosis and osteophyte formation of the SIJ than group A on every radiographs after postoperative 1 year. In group B, the number of fusion segments and age were statistically positively correlated with the degeneration of the SIJ.CONCLUSIONS: Degeneration of the SIJ revealed more rapid and more severe progression in lumbosacral fusion group than in lumbar fusion group. The number of fusion segments and age were positively correlated with the degeneration of the SIJ in lumbosacral fusion group. Therefore, these facts should be taken into account when performing spinal fusion.

Is Adjacent Segment Disease More Frequent in Proximal Levels in Comparison with Distal Levels? Based on Radiological Data of at Least 2 Years Follow Up with More than 2 Level Thoracolumbar Fusions

OBJECTIVE: The purpose of this retrospective study was to determine which of the proximal adjacent segment disease (ASD) and distal ASD was more prevalent and what parameters is more related to ASD in proximal levels and distal levels after more than 2 levels fusions. METHODS: The medical records were reviewed retrospectively for 856 cases. A total of 66 cases of ASD were enrolled. On pre-op magnetic resonance imaging, disc degeneration was measured at the upper and lower parts of surgically treated levels and confirmed by the commonly used Pfirrmann grade. Segmental flexibility in sagittal plane was embodied in segment range of motion (ROM) obtained through flexion and extension X-ray before surgery. Coronal angle was recorded as methods Cobb’s angle including fusion levels preoperatively. For the comparison of categorical variables between two independent groups, the chi-square test and Fisher exact test were performed. RESULTS: Proximal ASD and distal ASD were 37/856 (4.32%) and 29/856 (3.39%), respectively. The incidence of proximal ASD was relatively high but insignificant differences. In comparison between ASD group and non ASD group, proximal Pfirmman was higher in proximal ASD and distal Pfirmman was higher in distal ASD group (p=0.005, p<0.008, respectively). However, in the ROM, proximal ROM was higher in proximal ASD, but distal ROM was not different between the two groups (p<0.0001, p=0.995, respectively). Coronal angle was not quite different in both groups (p=0.846). CONCLUSION: In spite of higher frequency in ASD in proximal level in spinal fusion, it is not clear that incidence of ASD in proximal level is not higher than that of distal ASD group in more than 2 level thoracolumbar fusions. Not only Pfirrmann grade but also proximal segmental ROM is risk factor for predicting the occurrence of ASD in patients more than 2 level of thoracolumbar spine fusion operation excluding L5S1.

Clinical Outcomes of Percutaneous Endoscopic Lumbar Discectomy for Adjacent Lumbar Disc Herniation after Lumbar Posterolateral Fusion by Radiologic Evaluations

STUDY DESIGN: A retrospective study. OBJECTIVE: To analyze the effectiveness of percutaneous endoscopic lumbar discectomy (PELD) for adjacent lumbar disc herniation through radiologic evaluations. SUMMARY OF LITERATURE REVIEW: PELD minimizes posterior structural damage, allowing rapid rehabilitation. SUBJECTS AND METHODS: This study was conducted on 45 patients who were followed up for 1 year after PELD for adjacent lumbar disc herniation from March 2014 to February 2016. The modified Macnab criteria, the modified Suezawa and Schreiber score (MSS score), and visual analogue scales for the back (VAS-B) and legs (VAS-L) were evaluated. The disc height ratio and segmental angulation change were compared before posterolateral fusion and before PELD. Moreover, spinal stenosis was confirmed on magnetic resonance imaging (MRI) before PELD. RESULTS: Based on the modified Macnab criteria, 53.3% patients received an evaluation of at least “good,” and the mean MSS score improved from 4.77 to 6.99 at 1 year after the operation. The mean VAS-B score decreased from 7.02 to 4.67, and the mean VAS-L score decreased from 8.15 to 4.24 at 1 year after the operation. The mean disc height ratio was 87.1%, and the mean segmental angulation change was 6.5°, with a greater change in the “fair” or “poor” group, and the rate of spinal stenosis on MRI was also higher in the “fair” or “poor” group. CONCLUSION: The clinical outcomes of PELD, which is accompanied by degenerative changes on simple radiographic images such as disc space narrowing and increased segmental angulation or spinal stenosis on MRI, may not be satisfactory. Therefore, decisions regarding surgery should be made carefully in such cases.

Outcomes of Revision Surgery Following Instrumented Posterolateral Fusion in Degenerative Lumbar Spinal Stenosis: A Comparative Analysis between Pseudarthrosis and Adjacent Segment Disease

STUDY DESIGN: Retrospective study. PURPOSE: We examined the clinical and radiological outcomes of patients who received revision surgery for pseudarthrosis or adjacent segment disease (ASD) following decompression and instrumented posterolateral fusion (PLF). OVERVIEW OF LITERATURE: At present, information regarding the outcomes of revision surgery for complications such as pseudarthrosis and ASD following instrumented PLF is limited. METHODS: This study examined 60 patients who received PLF for degenerative lumbar spinal stenosis and subsequently developed pseudarthrosis or ASD leading to revision surgery. Subjects were divided into a group of 21 patients who received revision surgery for pseudarthrosis (Group P) and a group of 39 patients who received revision surgery for ASD (Group A). Clinical outcomes were evaluated using the visual analogue scales for back pain (VAS-BP) and leg pain (VAS-LP), the Korean Oswestry disability index (K-ODI), and each patient's subjective satisfaction. Radiological outcomes were evaluated from the extent of bone union, and complications in the two groups were compared. RESULTS: VAS-LP at final follow-up was not statistically different between the two groups (p =0.353), although VAS-BP and K-ODI at final follow-up were significantly worse in Group P than in Group A (all p <0.05), and only 52% of the patients in Group P felt that their overall well-being had improved following revision surgery. Fusion rates after the first revision surgery were 71% (15/21) in Group P and 95% (37/39) in Group A (p =0.018). The rate of reoperation was significantly higher in Group P (29%) than in Group A (5%) (p =0.021) due to complications. CONCLUSIONS: Clinical and radiological outcomes were worse in patients who had received revision surgery for pseudarthrosis than in those who had revision surgery for ASD. Elderly patients should be carefully advised of the risks and benefits before planning revision surgery for pseudarthrosis.

Comparative Analysis of Revision Surgery Groups between within 5 Years and More than 10 Years after Lumbar Spinal Fusion Due to Adjacent Segment Disease / 대한정형외과학회잡지

PURPOSE: The purpose of this study is to analyze the risk factors for early adjacent segment disease (EASD) in patients undergoing revision surgery within 5 years from the first operation as compared with those after more than 10 years. MATERIALS AND METHODS: A total of 755 patients with degenerative lumbar disease underwent lumbar spinal fusion of 3 or less segments between August, 1988 and May, 2009. Of these, 44 patients underwent revision surgery due to adjacent segment disease (ASD) until May, 2014. These patients presented with ASD, 19 and 13 of whom underwent revision surgery within 5 years and after more than 10 years of the first one, and were thus assigned to group A (n=19) and group B (n=13), respectively. Thirty-two of these patients were enrolled in this study and baseline and clinical characteristics, including sex, age, fusion method, preoperative diagnosis, the number of fused segments, fusion level, and radiological measurements were compared between the two groups. Radiological measurements included pre- and postoperative lumbar lordotic angle (LLA), pre- and postoperative fusion segment lordotic angle (FSLA), pre- and postoperative FSLA per level and the correction of LLA, FSLA, and FSLA per level. For statistical analysis, univariate analysis with the chi-square test was performed using SPSS 14.0. RESULTS: In group A, the number of patients undergoing posterior lumbar interbody fusion (PLIF) rather than posterolateral fusion, those with postoperative FSLA per level of <20° and the adjacent segment levels to L4-5 and L5-S1 was significantly larger compared with group B (p=0.018, 0.046, and 0.009, respectively. CONCLUSION: In conclusion, our results indicate that the degree of risk of EASD was relatively higher in association with PLIF, postoperative FSLA per level of <20° and the adjacent segment levels to L4-5 and L5-S1.

Analysis of Risk Factors of Adjacent Segment Disease with Lumbar and Lumbosacral Arthrodesis for the Degenerative Lumbar Spinal Disorders / 대한정형외과학회잡지

PURPOSE: The objective of this study is to confirm the effects of risk factors on Adjacent Segment Disease (ASD). MATERIALS AND METHODS: The subjects of this study were 793 patients who had degenerative lumbar spine disease and were followed-up for an average period of 7.2 years from January of 1999 to September of 2010 after undergoing spinal fusion. To confirm the risk factors, a study on patient factors, surgical factors and radiologic factors was performed. RESULTS: Of 793 patients, 69 patients (group A, 8.7%) underwent a secondary surgical treatment due to ASD. Age of patient, sex, bone mineral density, history of smoking and occupation were not statistically significant. Preoperative body mass index (BMI) (> or =25 kg/m2) and postoperative increase of BMI were the patient's factor in ASD (p=0.02, p<0.001). Regarding surgical factors, multilevel fusion (more than 3 levels) was higher risk in prevalence of ASD than short level fusion (p=0.01). Degeneration of intervertebral disc (p=0.01) and facet joints (p=0.02), and segmental instability (p=0.001) were also associated with the prevalence of ASD in radiologic factors. CONCLUSION: To prevent the occurrence of ASD after lumbosacral fusion, selection of the proper level of fusion preoperatively and modifying the life style with body weight control and reduction of hypermobility after fusion surgery are essential.

Kyphotic Neck and Correlation With Clinical Outcomes

STUDY DESIGN: A literature review regarding the correlation between a kyphotic neck and its clinical outcomes. OBJECTIVES: This review examines normal cervical alignment, methods for assessing alignment, a specific correlation between kyphotic neck and clinical outcomes, and indications and methods of surgical treatment. SUMMARY OF LITERATURE REVIEW: Cervical kyphotic deformity is problematic in terms of HRQOL due to nerve damage or loss of horizontal gaze. MATERIALS AND METHODS: Review of the literature. RESULTS: Cervical kyphosis can be caused by postlaminectomy, degenerative disc disease, and trauma, and the symptoms exhibit diverse clinical progression including compensatory mechanisms, adjacent segment disease, changes in quality of life, and cervical myelopathy. Given the serious complications of cervical surgery, we need a deep understanding of spine anatomy, preoperative planning, and correction methods. CONCLUSIONS: It is vital to investigate cervical sagittal alignment and to perform intensive treatment and corrective surgery to achieve better clinical outcomes.

Radiologic Changes of Operated and Adjacent Segments after Anterior Cervical Microforaminotomy

OBJECTIVE: Anterior cervical microforaminotomy (ACMF) is a motion-preserving surgical procedure. The purpose of this study is to assess radiologic changes of operated and adjacent segments after ACMF. METHODS: We retrospectively reviewed 52 patients who underwent ACMF between 1998 and 2008. From X-ray film-based changes, disc height and sagittal range of motion (ROM) of operated and adjacent segments were compared at preoperative and last follow-up periods. Radiological degeneration of both segments was analyzed as well. RESULTS: The mean follow-up period was 48.2 months. There were 78 operated, 52 upper adjacent, and 38 lower adjacent segments. There were statistically significant differences in the ROM and disc height of operated segment between preoperative and last follow-up periods. However, there were no statistically significant differences in the ROM and disc height of adjacent segment between both periods. Radiological degenerative changes of operated segments were observed in 30%. That of adjacent segments was observed in 11 and 11% at upper and lower segments, respectively. CONCLUSION: After mean 4-year follow-up periods, there were degenerative changes of operated segments. However, ACMF preserved motion and prevented degenerative changes of adjacent segments.

Artificial disc and vertebra system: a novel motion preservation device for cervical spinal disease after vertebral corpectomy

OBJECTIVE: To determine the range of motion and stability of the human cadaveric cervical spine after the implantation of a novel artificial disc and vertebra system by comparing an intact group and a fusion group. METHODS: Biomechanical tests were conducted on 18 human cadaveric cervical specimens. The range of motion and the stability index range of motion were measured to study the function and stability of the artificial disc and vertebra system of the intact group compared with the fusion group. RESULTS: In all cases, the artificial disc and vertebra system maintained intervertebral motion and reestablished vertebral height at the operative level. After its implantation, there was no significant difference in the range of motion (ROM) of C3-7 in all directions in the non-fusion group compared with the intact group (p>0.05), but significant differences were detected in flexion, extension and axial rotation compared with the fusion group (p<0.05). The ROM of adjacent segments (C3-4, C6-7) of the non-fusion group decreased significantly in some directions compared with the fusion group (p<0.05). Significant differences in the C4-6 ROM in some directions were detected between the non-fusion group and the intact group. In the fusion group, the C4-6 ROM in all directions decreased significantly compared with the intact and non-fusion groups (p<0.01). The stability index ROM (SI-ROM) of some directions was negative in the non-fusion group, and a significant difference in SI-ROM was only found in the C4-6 segment of the non-fusion group compared with the fusion group. CONCLUSION: An artificial disc and vertebra system could restore vertebral height and preserve the dynamic function of the surgical area and could theoretically reduce the risk of adjacent segment degeneration compared with the anterior fusion procedure. However, our results should be considered with caution because of the low power of the study. The use of a larger ...

Adjacent Segment Pathology after Lumbar Spinal Fusion

One of the major clinical issues encountered after lumbar spinal fusion is the development of adjacent segment pathology (ASP) caused by increased mechanical stress at adjacent segments, and resulting in various radiographic changes and clinical symptoms. This condition may require surgical intervention. The incidence of ASP varies with both the definition and methodology adopted in individual studies; various risk factors for this condition have been identified, although a significant controversy still exists regarding their significance. Motion-preserving devices have been developed, and some studies have shown their efficacy of preventing ASP. Surgeons should be aware of the risk factors of ASP when planning a surgery, and accordingly counsel their patients preoperatively.

Risk Factors for Adjacent Segment Disease Development after Lumbar Fusion

STUDY DESIGN: Retrospective cohort study. PURPOSE: To identify factors which may be important in the occurrence of symptomatic adjacent segment disease (ASD) after lumbar fusion. OVERVIEW OF LITERATURE: Many reports have been published about the risk factors for ASD after lumbar fusion. Despite on the great numbers of risk factors identified for ASD development, study results have been inconsistent and there is controversy regarding which are the most important. METHODS: This study evaluated 120 patients who underwent 360degrees fusion lumbar surgery from 2007 to 2012. We separated the population into two groups: the first group included 60 patients with long lumbar fusion (three or more levels) and the second group included 60 patients with short lumbar fusion (less than three levels). RESULTS: In the first group, symptomatic ASD was found in 19 cases during the one year follow-up. There were 14 cases with sagittal imbalance and 5 cases at the incipient stage of disc degeneration according to the preoperative magnetic resonance imaging. At the three year follow-up, symptomatic ASD was diagnosed in 31 cases, of which 17 patients had postoperative sagittal balance disturbance. In the second group, 10 patients had ASD at the one year follow-up. Among these cases, preoperative disc degenerative changes were identified in 8 patients. Sagittal imbalance was found only in 2 cases with symptomatic ASD at the one year follow-up. At the three year follow-up, the number of patients with symptomatic ASD increased to 14. Among them, 13 patients had initial preoperative adjacent disc degenerative changes. CONCLUSIONS: Patients with postoperative sagittal imbalance have a statistically significant increased risk of developing symptomatic ASD due to an overloading the adjacent segments and limited compensatory capacities due to the large number of fixed mobile segments. In the case of a short fixation, preoperative degenerative changes are more important factors in the development of ASD.

New Classification for Clinically Symptomatic Adjacent Segment Pathology in Cervical Disc Disease

STUDY DESIGN: Clinical adjacent segment pathology (CASP) is common after cervical disc surgery. A critical examination of 320 patients operated for cervical disc prolapse revealed that CASP can also occur in patients with congenital and degenerative fusion of cervical spine. This has not been studied in depth and there is a need for a practically applicable classification of CASP. PURPOSE: To develop a new classification scheme of CASP. OVERVIEW OF LITERATURE: A review of the literature did not reveal a practically applicable classification incorporating the occurrence of CASP in congenital and degenerative fusion cases. METHODS: This was a retrospective analysis of 320 patients operated (509 disc spaces) on for cervical disc prolapse. Cases (n=316) were followed-up for 3-11 years. Random sampling of 220 patients with postoperative magnetic resonance imaging (MRI) in 165 cases was analyzed. RESULTS: Six symptomatic CASP cases required resurgery (1.9%), eight cases involved MRI proven CASP with axial neck pain only and 13 patients were asymptomatic with radiological adjacent segment pathology (RASP). The frequency rate was 8.5% (27/316). Four cases of congenital or degenerative fusion of vertebra developed CASP requiring surgery. CASP is classified as primary or secondary follows. Primary A1 was congenital fusion of vertebra and primary A2 was degenerative fusion of the vertebra. Secondary, which was after cervical disc surgery, comprised B1 (RASP in asymptomatic patients), B2 (CASP in patients with axial neck pain), and B3 (CASP with myeloradiculopathy). B3 was subdivided into single-level CASP (B3a) and multiple-level CASP (B3b). CONCLUSIONS: Symptomatic CASP requiring resurgery is infrequent. CASP can occur in patients with congenital and degenerative fusion of the cervical spine. A new classification for CASP along with treatment strategy is proposed. Patients in Primary CASP and B3 CASP require resurgery while others require only observation.

Radiographic Assessment of Effect of Congenital Monosegment Synostosis of Lower Cervical Spine between C2-C6 on Adjacent Mobile Segments

STUDY DESIGN: A prospective radiographic study of cervical spine with congenital monosegment fusion. PURPOSE: To evaluate the effect of cervical synostosis on adjacent segments and the vertebral morphology. OVERVIEW OF LITERATURE: There are numerous clinical studies of adjacent segment disease (ASD) after monosegment surgical fusion. However, there was no report on ASD in the cervical spine with congenital monosegment synostosis. METHODS: Radiograms of 52 patients, aged 5 to 90 years, with congenital monosegment synostosis (CMS) between C2 and C6, who complained of neck/shoulder discomfort or pain were studied. 51 were normally aligned and one was kyphotically aligned. RESULTS: Spondylosis was not found in the patients below 35 years of age. Only 12 out of 24 patients with normally aligned C2-3 synostosis had spondylosis in 19 more caudal segments, and only one at C3-4. A patient with kyphotic C2-3 had spondylolysis at C3-4. In 8 patients with C3-4 synostosis, spondylosis was found in only 9 caudal segments (4 at C4-5, 4 at C5-6, and 1 at C6-7). The caudate C4-5 disc was the most liable to degenerate in comparison with other caudate segments. Caudal corporal flaring and inwaisting of the synostotic vertebra were the features that were the most evident. In 2 of 9 C4-5 and 7 out of 10 C5-6 synostosis patients, spondylosis was found at the two adjacent cephalad and caudate segments, respectively. Only corporal inwaisting without flaring was found. In all cases, spondylosis was confined to the adjacent segments. More advanced spondylosis was found in the immediate caudal segment than the cephalad one. CONCLUSIONS: It is concluded that spondylosis at the mobile segments in a synostotic spine is thought to be a fusion-related pathology rather than solely age-related disc degeneration. Those data suggested that CMS definitely precipitated the disc degeneration in the adjacent segments.

Correlation of Adjacent Segmental Disease with Tilt Angles of the Upper and Lower Instrumented Vertebra in the Degenerative Lumbar Scoliosis

STUDY DESIGN: Retrospective study. OBJECTIVES: To evaluate the correlation of adjacent segmental disease with tilt angles of the upper and lower instrumented vertebra after instrumented posterolateral fusion for degenerative lumbar scoliosis. SUMMARY OF LITERATURE REVIEW: There has been no study of radiologic measurement and decision of fusion level using the angle of pedicle screws inserted for treatment of degenerative lumbar scoliosis. MATERIALS AND METHODS: From 2004 to 2008, 74 patients that underwent decompression and posterolateral fusion for degenerative lumbar scoliosis were included in this study. In all cases, instrumentation and posterolateral fusion were both performed. The sex ratio was 31:43, the mean age was 68.7 years and the mean follow up duration was 37.4 months. The angle between each upper end plate of the upper vertebral body and lower end plate of the lower vertebral body of the fusion, and the line parallel to the axis of the sagittal line of vertebrae was each defined as UIV-a and LIV-b. The correlation of development of adjacent segment disease and UIV-a, and LIV-b angle was investigated. RESULTS: Sum of the absolute value of UIV-a and LIV-b had a statistically significant positive correlation with that of adjacent segment disease. Also, UIV-a alone, had a statistically positive correlation with the development of proximal adjacent segment disease. CONCLUSIONS: Since it is proven that adjacent segment disease has positive correlation with the sum of the absolute value of UIV-a and LIV-b, the extent of fusion should be adjusted to make the line parallel to the line perpendicular to the sagittal surface.

A Comparison of Adjacent Segment Diseases Above One Versus Above Two Vertebral Segment after Spinal Fusion of the Degenerative Lumbar Disease

STUDY DESIGN: Retrospective study. OBJECTIVE: To compare patients who underwent spinal revision surgery of adjacent segment degeneration with above one and above two vertebral segment preceded by initial spinal fusion surgery. SUMMARY OF LITERATURE REVIEW: The adjacent segment disease(ASD) occurs more frequently at the more proximal segment of the spinal fusion. Also, the preexisting degenerative segments (with discs or facet joints) not included in the fusion procedure, fusion segmental sagittal angle, fixed appliances method, gender, and age, have been accepted as the causes. MATERIALS AND METHODS: The patients were watched over a year after the spinal revision operation followed by initial spinal fusion of single or multiple segments; the subjects were limited to 41 patients. The average age, entity of diseases, average duration between the initial spinal fusion and the revision surgery, multiple clinical and radiographic parameters were evaluated and compared. RESULTS: Using the UCLA grade of intervertebral disc degeneration, the average grade of 1 level upper segment was 2.2 in group A and 1.9 in group B without statistical significance(p=0.426). However, the average grade of 2-level upper segment was 1.8 in group A and 2.4 in group B with significant difference(p=0.021). There was no statistical difference in other factors between the two groups. CONCLUSIONS: Patients with ASD of above two-vertebral segment after spinal fusion were more severe in disc degeneration than those with ASD of above one vertebral segment before initial spinal fusions.

Acute Paraplegia Secondary to Thoracic Disc Herniation of the Adjacent Segment Following Thoracolumbar Fusion and Instrumentation

Proximal junctional disease is a well-recognized postoperative phenomenon in adults who are undergoing long thoracolumbar fusion and instrumentation, and is attributed to increased a junctional stress concentration. In general, the onset of symptoms in these patients is insidious and the disease progresses slowly. We report on a contrary case of rapidly progressing paraplegia secondary to acute disc herniation at the proximal adjacent segment after long posterior thoracolumbar fusion with cement augmentation at the upper instrumented vertebra and the supra-adjacent vertebra. The patient was treated with a discectomy through the costo-transverse approach combined with extension of the posterior instrumentation. The patient's neurological status improved markedly. Stress concentration at the proximal junction disc space may have caused accelerated disc degeneration which in turn lead to this complication.