Surgical treatment of adjacent instability after lumbar spine fusion

A novel guide device for pedicle screw insertion using three-dimensional preoperative planning in open lumbar spinal surgery: a comparative retrospective study

OBJECTIVE

Pedicle screw stabilization (PSS) surgeries for spinal instability are still the most effective treatment approach. The use of preoperative planning can minimize the complications related to transpedicular screw (TPS) misplacement. The study aimed to evaluate the surgical outcomes of a guide device developed to improve the accuracy of the free-hand technique using three-dimensional planning in PSS.

PATIENTS AND METHODS

Patients with degenerative spinal diseases who underwent open PSS between 2019 and 2022 were evaluated retrospectively. FG group included patients who were operated on using the fluoroscopy alone with preoperative two-dimensional planning. AFG group included patients who were operated on using a guide advice-assisted technique with preoperative 3DP. Between-group comparisons were performed.

RESULTS

A total of 143 patients with a mean age of 59.6 years were included in the study. 71 patients were assessed in the FG group and 72 patients in the AFG group. Between-group comparisons regarding demographics, etiologies, radiation exposure, and functional improvements showed no significant differences (p > 0.05). Although the accuracy of TPSs positioning was 94.2% and 96.5% in the 2DG and 3DG, the difference between the groups was not statistically significant. The statistically significant differences regarding the upper-level facet joint violation and pedicle breach rates were lower in the AFG group (p < 0.0001; X2 = 19.57) and (p < 0.0001; X2 = 25.3), respectively.

CONCLUSION

Using a guide device associated with preoperative 3PD reduced the upper-level facet joint violation and pedicle breach rates in open PSS surgeries performed by free-hand technique for degenerative spinal diseases.

Completely Minimally Invasive Implant Removal and Transforaminal Lumbar Interbody Fusion for Adjacent Segment Disease: Case Series and Operative Video

BACKGROUND AND OBJECTIVES

Adjacent segment disease is a relatively common late complication after lumbar fusion. If symptomatic, certain patients require fusion of the degenerated adjacent segment. Currently, there are no posterior completely minimally invasive techniques described for fusion of the adjacent segment above or below a previous fusion. We describe here a novel minimally invasive technique for both implant removal (MIS-IR) and adjacent level transforaminal lumbar interbody fusion (MIS-TLIF) for lumbar stenosis.

METHODS

Demographic, surgical, and radiographic outcome data were collected for patients with lumbar stenosis and previous lumbar fusion, who were treated with MIS-IR and MIS-TLIF through the same incision. Radiographic outcomes were assessed postoperatively and complications were assessed at the primary end point of 3 months.

RESULTS

A total of 14 patients (7 female and 7 male), with average age 64.6 years (SD 13.4), were included in this case series. Nine patients had single-level MIS-IR with single-level MIS-TLIF. Three patients had 2-level MIS-IR with single-level MIS-TLIF. Two patients had single-level MIS-IR with 2-level MIS-TLIF. Only 1 patient had a postoperative complication-hematoma requiring same-day evacuation. There were no other complications at the primary end point and no fusion failure at the hardware removal levels to date (average follow-up, 11 months). Average increases in posterior disk height and foraminal height after MIS-TLIF were 4.44, and 2.18 mm, respectively.

CONCLUSION

Minimally invasive spinal IR can be successfully completed along with adjacent level TLIF through the same incisions, via an all-posterior approach.

Vertebral Bone Quality Score as a Predictor of Adjacent Segment Disease After Lumbar Interbody Fusion

BACKGROUND AND OBJECTIVE

With lumbar spine fusion being one of the most commonly performed spinal surgeries, investigating common complications such as adjacent segment disease (ASD) is a high priority. To the authors' knowledge, there are no previous studies investigating the utility of the preoperative magnetic resonance imaging-based vertebral bone quality (VBQ) score in predicting radiographic and surgical ASD after lumbar spine fusion. We aimed to investigate the predictive factors for radiographic and surgical ASD, focusing on the predictive potential of the VBQ score.

METHODS

A single-center retrospective analysis was conducted of all patients who underwent 1-3 level lumbar or lumbosacral interbody fusion for lumbar spine degenerative disease between 2014 and 2021 with a minimum 12 months of clinical and radiographic follow-up. Demographic data were collected, along with patient medical, and surgical data. Preoperative MRI was assessed in the included patients using the VBQ scoring system to identify whether radiographic ASD or surgical ASD could be predicted.

RESULTS

A total of 417 patients were identified (mean age, 59.8 ± 12.4 years; women, 54.0%). Eighty-two (19.7%) patients developed radiographic ASD, and 58 (13.9%) developed surgical ASD. A higher VBQ score was a significant predictor of radiographic ASD in univariate analysis (2.4 ± 0.5 vs 3.3 ± 0.4; P < .001) and multivariate analysis (odds ratio, 1.601; 95% CI, 1.453-1.763; P < .001). For surgical ASD, a significantly higher VBQ score was seen in univariate analysis (2.3 ± 0.5 vs 3.3 ± 0.4; P < .001) and served as an independent risk factor in multivariate analysis (odds ratio, 1.509; 95% CI, 1.324-1.720; P < .001). We also identified preoperative disk bulge and preoperative existence of adjacent segment disk degeneration to be significant predictors of both radiographic and surgical ASD. Furthermore, 3-level fusion was also a significant predictor for surgical ASD.

CONCLUSION

The VBQ scoring system might be a useful adjunct for predicting radiographic and surgical ASD.

Comparison between oblique lumbar interbody fusion and posterior lumbar interbody fusion for the treatment of lumbar degenerative diseases: a systematic review and meta-analysis

BACKGROUND

Although oblique lumbar interbody fusion (OLIF) has produced good results for lumbar degenerative diseases (LDDs), its efficacy vis-a-vis posterior lumbar interbody fusion (PLIF) remains controversial. This meta-analysis aimed to compare the clinical efficacy of OLIF and PLIF for the treatment of LDDs.

METHODS

A comprehensive assessment of the literature was conducted, and the quality of retrieved studies was assessed using the Newcastle-Ottawa Scale. Clinical parameters included the visual analog scale (VAS), and Oswestry Disability Index (ODI) for pain, disability, and functional levels. Statistical analysis related to operative time, intraoperative bleeding, length of hospital stay, lumbar lordosis angle, postoperative disc height, and complication rates was performed. The PROSPERO number for the present systematic review is CRD42023406695.

RESULTS

In total, 574 patients (287 for OLIF, 287 for PLIF) from eight studies were included. The combined mean postoperative difference in ODI and lumbar VAS scores was - 1.22 and - 0.43, respectively. In postoperative disc, height between OLIF and PLIF was 2.05. The combined advantage ratio of the total surgical complication rate and the mean difference in lumbar lordosis angle between OLIF and PLIF were 0.46 and 1.72, respectively. The combined mean difference in intraoperative blood loss and postoperative hospital stay between OLIF and PLIF was - 128.67 and - 2.32, respectively.

CONCLUSION

Both the OLIF and PLIF interventions showed good clinical efficacy for LDDs. However, OLIF demonstrated a superior advantage in terms of intraoperative bleeding, hospital stay, degree of postoperative disc height recovery, and postoperative complication rate.

Percutaneous Endoscopic Transforaminal Lumbar Interbody Fusion (PETLIF): Current Techniques, Clinical Outcomes, and Narrative Review

Full endoscopic techniques are becoming more popular for degenerative lumbar pathologies. Percutaneous endoscopic lumbar interbody fusion (PETLIF) is a minimally invasive surgical technique for spondylolisthesis and lumbar spinal canal stenosis with instability. Nagahama first introduced PETLIF in 2019. This study investigated the clinical outcomes and complications of 24 patients who underwent PETLIF in our facility and compared them with previous studies. Literature searches were conducted on PubMed and Web of Science. The PETLIF surgical technique involves three steps to acquire disc height under general anesthesia. The procedure includes bone harvesting, spondylolisthesis reduction, endoscopic foraminoplasty, disc height expansion using an oval dilator, and intervertebral disc curettage. A cage filled with autologous bone is inserted into the disc space and secured with posterior fixation. Patients underwent PETLIF with an average operation time of 130.8 min and a blood loss of 24.0 mL. Postoperative hospital stays were 9.5 days. Improvement in VAS, disc height, spinal canal area, and % slip was observed, while lumbar lordosis remained unchanged. Complications included end plate injury, subsidence, and exiting nerve root injury. The differences between PETLIF and the extracted literature were found in patients' age, direct decompression, epidural or local anesthesia, approach, order of PPS, and cage insertion. In conclusion, PETLIF surgery is a practical, minimally invasive surgical technique for patients with lumbar degenerative diseases suffering from back and leg pain, demonstrating significant improvements in pain scores. However, it is essential to carefully consider the potential complications and continue to refine the surgical technique further to enhance the safety and efficacy of this procedure.

Adjacent Segment Disease After Spinal Fusion

» Adjacent segment disease is characterized by a degenerative process adjacent to a previously fused spine segment, with new onset of clinical symptoms such as radiculopathy, myelopathy, or instability.» Etiology is related to the natural history of the disease process, increased biomechanical stress at adjacent segments, clinical factors specific to the individual patient, intraoperative factors, and malalignment.» Treatment is usually nonoperative, but surgical intervention can be indicated. Decompression and fusion remain the mainstay of operative treatment, and isolated decompression should be considered in specific cases.» Further randomized controlled trials are needed to establish how the treatment should progress, particularly with the development of minimally invasive and endoscopic surgery.

Comparing oblique lumbar interbody fusion with lateral screw fixation and percutaneous endoscopic transforaminal discectomy (OLIF-PETD) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) for the treatment of lumbar disc herniation complicated with lumbar instability

OBJECTIVE

To evaluate the early clinical effect of oblique lumbar interbody fusion with lateral screw fixation and percutaneous endoscopic transforaminal discectomy (OLIF-PETD) in the treatment of lumbar disc herniation with lumbar instability.

METHODS

A total of 22 patients with lumbar disc herniation and lumbar instability from August 2017 to August 2019 were enrolled in this retrospective study. The general information, perioperative indicators and complications were recorded. The clinical outcomes and radiological outcomes were evaluated before the operation, seven days after the operation, and at the last follow-up. Vertebral fusion and degree of multifidus muscle injury were evaluated at the last follow-up.

RESULTS

In this study, OLIF + PETD showed shorter incision length compared to the MIS-TLIF (P < 0.001). In the two groups, the clinical outcomes and radiological outcomes were significantly improved compared with the preoperative (P < 0.001). At the seven days after the operation and the last follow-up, the VAS of OLIF + PETD group was lower than that of MIS-TLIF group (P < 0.05). OLIF + PETD could give superior outcome in restoring disc height (P < 0.001), but the fusion segment angle of OLIF + PETD group was larger compared to the MIS-TLIF group seven days after the operation and at the last follow-up (P < 0.05). In addition, the fusion rate was not significantly different between the two groups (P > 0.05), but OLIF + PETD could avoid the multifidus injury (P < 0.001).

CONCLUSION

Compared to MIS-TLIF, OLIF-PETD can achieve satisfactory decompression effects and fusion rates with less multifidus injury and postoperative low back pain, which may be an alternative choice for the treatment of lumbar disc herniation combined with lumbar instability.

Transforaminal Endoscopic Decompression for Foraminal Stenosis: Single-Arm Meta-Analysis and Systematic Review

OBJECTIVE

The objective of the study was to conduct a single-arm meta-analysis and comprehensive systematic review to identify the efficacy and safety of transforaminal endoscopic surgery for the treatment of lumbar foraminal stenosis (LFS).

METHODS

The meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. The PubMed, Web of Science, and Embase databases were searched from inception to February 20, 2022. Primary research results were visual analog scale scores, Oswestry Disability Index scores, MacNab criterion scores, and reported adverse events. Subgroup analyses were performed on the primary outcome to evaluate the potential effects of several clinical factors that affected the results.

RESULTS

Of the 2020 studies identified, 9 met the inclusion criteria, and 316 participants were eligible for meta-analysis. The meta-analysis results found that transforaminal endoscopic surgery for the treatment of LFS was associated with a significant improvement in postoperative 12-month clinical indicators: 8 studies reported improvements in visual analog scale scores: -5.38, Oswestry Disability Index scores: -40.44, and MacNab criterion scores: odds ratio = 0.86; 8 studies reported 11.53% adverse events occurred in a total of 295 patients, and the most commonly reported event was transient postoperative dysesthesia, which occurred in 26 patients in a total of 6 studies with 240 patients (10.83%).

CONCLUSIONS

Transforaminal endoscopic surgery positively affects postoperative LFS patients' clinical indicators; however, high-level literature with randomized controlled trials is needed to confirm this technique's applicability in LFS.

Effect of sagittal screw angle and distance of screw apex to superior endplate on adjacent segment disease after posterolateral lumbar fusion: a retrospective study

Background

Numerous complications of lumbar fusion surgery have been reported, with adjacent segment disease (ASD) being one of the most important. Few studies describe the effect of sagittal, horizontal screw angles and distance of pedicle screw apex to superior endplate on the incidence of ASD in lumbar spine. The purpose of this retrospective study is to evaluate the hypothesis that unsatisfactory pedicle screw insertion positions would increase the likelihood of ASD.

Methods

Outpatients with lumbar spinal stenosis underwent posterolateral lumbar fusion at L4-S1 with a least 2-year follow-up were studied. ASD at L3–L4 was defined as a condition in which intervertebral disk narrowing, posterior vertebral opening, and vertebral slippage progress at the last follow-up in comparison with the postoperative. Independent t test was performed to compare data between two groups; Spearman analysis was performed to analyze the relationship between two continuous variables. Multivariate binary logistic models were performed to identify the independent risk factors of ASD. The receiver operating characteristic (ROC) curve was performed to measure model discrimination and Hosmer–Lemeshow (H–L) test was used to measure calibration. ROC curve evaluated the discrimination ability of sagittal screw angle and distance in predicting incidence of ASD.

Results

Patients in ASD group exhibit higher incidence of osteoporosis, higher Visual analogue scale (VAS), Oswestry disability index (ODI), bigger sagittal screw angle, shorter distance of pedicle screw apex to superior endplate than those in non-ASD group (p < 0.05). VAS, ODI at the last follow-up were positively correlated with Pfirrmann grade of L3–4 disk and sagittal screw angle, while negatively correlated with distance of screw apex to superior endplate (p < 0.05). Multivariate binary logistic model indicated that follow-up time (odds ratio [OR] 1.637, 95% confidence interval [CI] 1.186–2.260), distance of screw apex to superior endplate (OR 0.150, 95% CI 0.067–0.336), sagittal screw angle (OR 2.404, 95% CI 1.608–3.594) were statistically significant. The models showed great discrimination and calibration. The area under the curve of ASD identified by sagittal angle and distance was 0.895 and the cut-off values were 5.500° and 6.250 mm, respectively.

Conclusion

Sagittal screw angle and distance of screw apex to superior endplate were significantly associated with the risk of ASD.

Adjacent segment disease after minimally invasive transforaminal lumbar interbody fusion for degenerative lumbar diseases: incidence and risk factors

Study design

Retrospective study.

Objectives

To explore the incidence and risk factors for symptomatic adjacent segment disease (ASD) in patients enveloped in degenerative lumbar diseases after minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF).

Methods

Data were retrospectively analyzed on 744 patients who underwent MIS-TLIF for degenerative lumbar diseases in our hospital from October 2012 to December 2018. The patients were divided into the ASD group and non-ASD (N-ASD) group on the basis of developing ASD at follow-up, and then the incidence of ASD was calculated. Clinical and radiological risk factors were assessed over time to determine their association with ASD by excluding less important factors.

Results

Data were missing for 26 patients, while a total of 718 patients were successfully monitored after MIS-TLIF. Of the 718 individuals participated in the study, 34 (4.7%) patients plagued by ASD required surgical intervention. The average onset time of ASD was 62.7 ± 15.1 months. Univariate analysis results shows that age, bone mineral density (BMD), body mass index (BMI), preoperative adjacent intervertebral disc height and preoperative adjacent segment disc degeneration were significantly different between the ASD and N-ASD groups (p < 0.05). The logistic regression analysis results demonstrated that BMD (p = 0.039, OR = 0.986, 95% CI 0.899–1.115), BMI (p = 0.041, OR = 1.119, 95% CI 1.103–2.397), and preoperative adjacent intervertebral disc degeneration (p = 0.023, OR = 1.215, 95% CI 1.015–1.986) may be seen as risk factors for ASD after MIS-TLIF.

Conclusions

The incidence of ASD was about 4.7% in patients suffer from degenerative lumbar diseases after MIS-TLIF. BMD, BMI and preoperative adjacent intervertebral disc degeneration might be the risk factors for the occurrence of ASD after MIS-TLIF. Our research also suggested that patients with lower BMD, higher BMI and disc preoperative adjacent segment disc degeneration were more likely to develop ASD after MIS-TLIF.

Incidence and risk factors of vertebral body collapse after posterior instrumented spinal fusion in elderly patients: An observational study

This study investigates the incidence and risk factors of new vertebral body collapse (VC) after posterior instrumented spinal fusion in patients older than 70 years. This retrospective study analyzed the data of elderly patients who underwent posterior instrumented spinal fusion in the thoracolumbar spine between January 2013 and December 2017. The 2 subsamples comprised of patients who had experienced vertebral compression fracture (VCF) before the index spinal surgery (group 1, n = 324) and those who had not (group 2, n = 1040). We recorded and analyzed their baseline characteristics, their underlying comorbidities, and the details of their current instrumented spinal fusion. The incidences of new VC and screw loosening were recorded. In groups 1 and 2, the incidences of new VC were 31.8% and 22.7%, respectively, and those of new VC with screw loosening were 25.6% and 33%, respectively. The risk factor was upper screw level at the thoracolumbar junction (hazard ratio [HR] = 2.181, 95% confidence interval [CI]: 1.135-4.190) with previous VCF. The risk factors were age ≥ 80 years (HR = 1.782, 95% CI: 1.132-2.805), instrumented levels > 4 (HR = 1.774, 95% CI: 1.292-2.437), and peptic ulcer (HR = 20.219, 95% CI: 2.262-180.731) without previous VCF. Clinicians should closely monitor new VC after posterior instrumented spinal fusion in elderly patients with previous VCF with upper screw level at the thoracolumbar junction and in patients without previous VCF aged ≥ 80 years, with instrumented levels > 4 and peptic ulcer.

Assessment of vertebral bone mineral density and stand-alone oblique lumbar interbody fusion for adjacent segment disease and primary lumbar degenerative diseases

PURPOSE

To evaluate the vertebral bone mineral density and the value of stand-alone oblique lumbar interbody fusion (SA OLIF) for the management of single-level adjacent segment disease (ASD) and primary lumbar degenerative diseases.

PATIENTS AND METHODS

Seventy-eight patients undergoing single-level SA OLIF was divided into index surgery group (n = 36) or revision surgery group (n = 42) at single center. The vertebral body Hounsfield units (HU) value was measured to assess bone mineral density of operated level by the preoperative CT. The following data were retrospectively collected and compared between the two groups: demographic, surgical data, clinical results, and complications.

RESULTS

No differences were found between the two groups in surgical data. The fusion segment HU values in the revision group were significantly higher than that in the index group (147.4 ± 35.3 vs 129.2 ± 38.4 p = .033). There were significant differences while comparing fusion segment HU values to L1-L4 horizontal plane (147.4 ± 35.3 vs 126.1 ± 28.4, p = .000) and L1 (147.4 ± 35.3 vs 126.8 ± 26.2, p = .000) in revision group, meanwhile, no statistically significant difference was observed in index group (p > .05). The cage subsidence was observed in the revision group (n = 2) and index group (n = 9) (p = .045). The patients with cage subsidence had significantly lower vertebral HU values.

CONCLUSION

SA OLIF is valid alternative to the traditional posterior approach in the management of ASD with good clinical outcomes at short-term follow-up. Increased HU values of fusion segment may play a role in the management of ASD by SA OLIF.

Early Outcomes of 3D-printed Porous Titanium versus Polyetheretherketone (PEEK) Cage Implantation for Standalone Lateral Lumbar Interbody Fusion in the Treatment of Symptomatic Adjacent Segment Degeneration

OBJECTIVE

This study compared outcomes of 3D-printed porous titanium (Ti) versus polyetheretherketone (PEEK) cage implantation for standalone lateral lumbar interbody fusion (SA-LLIF) in the treatment of symptomatic adjacent segment degeneration (ASD).

METHODS

44 patients (59 levels) underwent SA-LLIF with Ti or PEEK cages between 10/2016 and 07/2020. The primary outcome was cage subsidence according to Marchi et al. Secondary outcomes included revision/recommendations for revision surgery, back/leg pain severity, changes in disc/foraminal height and global/segmental lumbar lordosis.

RESULTS

44 patients (21 female) were included with a mean age at surgery of 61.8±11.5 years, average radiological follow-up of 12.5±8.2 and clinical follow-up of 11.0±7.1 months. The overall subsidence rate was significantly less in the Ti versus PEEK group (20% vs. 58.8%; p=0.004). Revision was recommended to none of the patients in the Ti and 3 in the PEEK group (p=0.239). Furthermore, patients in the Ti group showed significantly better improvement in back pain NRS score (p=0.001). Disc height (p<0.001) and foraminal height restoration (p=0.011) were statistically significant in the Ti group, whereas only disc height restoration was significant in the PEEK group (p=0.003).

CONCLUSION

In patients undergoing SA-LLIF for ASD treatment, 3D-printed Ti cages had significantly lower overall subsidence rate compared to PEEK cages. Furthermore, Ti cages resulted in fewer recommendations for revision surgery. Whether greater pain reduction in the Ti group is associated with earlier or higher fusion rates needs to be further elucidated.

Preoperative Pelvic Incidence Minus Lumbar Lordosis Mismatch in Repeat Posterior Lumbar Interbody Fusion Induces Subsequent Corrective Long Fusion

OBJECTIVE

Only a few studies have addressed clinical outcomes of revision surgery for adjacent segment disease. The purpose of this study was to elucidate clinical outcomes of second (repeat) posterior lumbar interbody fusion (PLIF) by focusing on the relationship between clinical outcomes and spinopelvic parameters and predisposing factors requiring subsequent corrective long fusion after repeat PLIF.

METHODS

We analyzed the data of 47 patients ≥40 years old who underwent repeat PLIF after single-segment PLIF owing to adjacent segment disease. The correlation between clinical outcomes and radiographic parameters was investigated. Patient demographics and radiographic parameters were compared between patients with and without subsequent corrective long fusion.

RESULTS

Japanese Orthopaedic Association score at final follow-up was 13.4, and the recovery rate was 37.2%. All sagittal parameters except pelvic tilt and C7-central sacral vertical line at final follow-up showed weak to moderate (|r| = 0.30-0.56) correlation with clinical scores. Finally, 11% of patients required subsequent long corrective fusion. Pelvic incidence minus lumbar lordosis (PI-LL) mismatch (cutoff value of 27.5°) and thoracic kyphosis (cutoff value of 12.5°) before repeat PLIF were identified as predisposing factors for subsequent long corrective fusion.

CONCLUSIONS

The clinical outcomes of repeat PLIF were inferior to outcomes of primary PLIF. Once PI-LL mismatch occurs after initial PLIF, it will be difficult to resolve the PI-LL mismatch during the second PLIF. To stop the chain of reoperations in patients whose preoperative PI-LL exceeds 27.5° before repeat PLIF, corrective long fusion may be a surgical option to consider.

Patient-specific statistical shape modeling for optimal spinal sagittal alignment in lumbar spinal fusion

PURPOSE

The present study compared patients developing ASD after L4/5 spinal fusion with a control group using a patient-specific statistical shape model (SSM) to find alignment-differences between the groups.

METHODS

This study included patients who had undergone spinal fusion at L4/5 and either remained asymptomatic (control group; n = 25, follow-up of > 4 years) or required revision surgery for epifusional ASD (n = 22). Landmarks on preoperative and postoperative lateral radiographs were annotated, and the optimal spinal sagittal alignment was calculated for each patient. The two-dimensional distance from the SSM-calculated optimum to the actual positions before and after fusion surgery was compared.

RESULTS

Postoperatively, the additive mean distance from the SSM-calculated optimum was 86.8 mm in the ASD group and 67.7 mm in the control group (p = 0.119). Greater differences were observed between the groups with a larger distance to the ideal in patients with ASD at more cranial levels. Significant difference between the groups was seen postoperatively in the vertical distance of the operated segment L4. The patients with ASD (5.69 ± 3.0 mm) had a significant greater distance from the SSM as the control group (3.58 ± 3.5 mm, p = 0.034).

CONCLUSION

Patients with ASD requiring revision after lumbar spinal fusion have greater differences from the optimal spinal sagittal alignment as an asymptomatic control group calculated by patient-specific statistical shape modeling. Further research might help to understand the value of SSM, in conjunction with already established indexes, for preoperative planning with the aim of reducing the risk of ASD.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Stand-Alone Posterior Expandable Cage Technique for Adjacent Segment Degeneration with Lumbar Spinal Canal Stenosis: A Retrospective Case Series

Background and Objectives: Symptomatic adjacent segment degeneration (ASD) with lumbar spinal canal stenosis (LSCS) is a common complication after spinal intervention, particularly interbody fusion. Stand-alone posterior expandable cages enable interbody fusion with preservation of the previous operation site, and screw-related complications are avoided. Thus, the aim of this study was to investigate the clinicoradiologic outcomes of stand-alone posterior expandable cages for ASD with LSCS. Materials and Methods: Patients with persistent neurologic symptoms and radiologically confirmed ASD with LSCS were evaluated between January 2011 and December 2016. The five-year follow-up data were used to evaluate the long-term outcomes. The radiologic parameters for sagittal balance, pain control (visual analogue scale), disability (Oswestry Disability Index), and early (peri-operative) and late (implant) complications were evaluated. Results: The data of 19 patients with stand-alone posterior expandable cages were evaluated. Local factors, such as intervertebral and foraminal heights, were significantly corrected (p < 0.01 and p < 0.01, respectively), and revision was not reported. The pain level (p < 0.01) and disability rate (p < 0.01) significantly improved, and the early complication rate was low (n = 2, 10.52%). However, lumbar lordosis (p = 0.62) and sagittal balance (p = 0.80) did not significantly improve. Furthermore, the rates of subsidence (n = 4, 21.05%) and retropulsion (n = 3, 15.79%) were high. Conclusions: A stand-alone expandable cage technique should only be considered for older adults and patients with previous extensive fusion. Although this technique is less invasive, improves the local radiologic factors, and yields favorable clinical outcomes with low revision rates, it does not improve the sagittal balance. For more widespread application, the strength of the cage material and high subsidence rates should be improved.

Interspinous Process Fixation Device Versus Extended Pedicle Screw Fixation for Symptomatic Adjacent Segment Disease: 3-Year Retrospective Study

OBJECTIVE

In the present study, we compared the clinical and radiographic outcomes of an interspinous process fixation device (IFD) with those of extended pedicle screw fixation (PSF) for symptomatic adjacent segment disease (ASD) after lumbar fusion.

METHODS

The data from 109 patients with ASD treated with IFD (n = 48) or extended PSF (n = 61) from January 2009 to January 2016 were reviewed retrospectively. The clinical outcomes were measured using a visual analog scale (VAS) and the Oswestry disability index. The radiographic outcomes included the fusion rate, incidence of cage subsidence, and additional radiographic ASD.

RESULTS

The mean incision length, operative time, blood loss, and length of hospital stay were significantly lower in the IFD group (P < 0.001). Postoperative back and leg pain were relieved in both groups (P < 0.001). The mean preoperative VAS scores were 8.3 ± 1.3 and 8.5 ± 1.1 in the IFD and PSF groups and had improved to 2.8 ± 1.1 and 2.7 ± 1.2 after 36 months, respectively (P < 0.001). At 36 months postoperatively, 10 of the 56 patients (17.9%) in the PSF group had developed additional radiographic ASD compared with 2 of 44 patients (4.5%) in the IFD group.

CONCLUSION

Our results have demonstrated that in the treatment of symptomatic ASD, comparable clinical and radiologic outcomes can be achieved using IFD, which has a shorter skin incision, shorter operative time, less intraoperative blood loss, and shorter hospital stay than the extended PSF technique. Although not statistically significant, the IFD resulted in a lower ASD incidence compare with the PSF technique. Thus, IFD might be an alternative surgical method for symptomatic ASD after lumbar spine fusion.

Risk Factor Analysis of the Incidence of Subsequent Adjacent Vertebral Fracture After Lumbar Spinal Fusion Surgery with Instrumentation

OBJECTIVE

This study aimed to evaluate the risk factors for adjacent vertebral compression fractures after lumbar spinal fusion with instrumentation.

METHODS

A total of 669 patients who received lumbar instrumented spinal fusion between January 2012 and December 2015 were divided into 2 groups according to whether the adjacent vertebral body was fractured. The covariates recorded were age, sex, bone mineral density, and the number of fixed segments. The anatomic variables were pelvic incidence angle (PI), preoperative lumbar lordosis angle (Pre-LL), postoperative lumbar lordosis angle (Post-LL), Pre-LL minus Post-LL (Loss of LL), postoperative pelvic tilt (Post-PT), postoperative sacral slope, Pre-PI-LL mismatch (Pre-PI minus Pre-LL), and Post-PI-LL mismatch (Post-PI minus Post-LL). A 1-way analysis of variance (ANOVA) was performed with the aforementioned parameters, and binary logistic regression analysis was used to determine the relative risk factors.

RESULTS

The 669 patients were followed-up for a mean of 2.7 ± 1.1 years (range, 2-4 years). Twenty-seven patients demonstrated fractures in the adjacent vertebral body after surgery. Analysis by 1-way ANOVA demonstrated that age, PI, Pre-LL, Post-LL, Loss of LL, Post-PI-LL mismatch, Post-PT, and osteoporosis were potential risk factors (all parameters, P < 0.001). Furthermore, binary logistic regression analysis showed that a large Loss of LL, osteoporosis, and old age were also risk factors for adjacent vertebral compression fractures.

CONCLUSIONS

A greater Loss of LL, osteoporosis, and advanced age may be risk factors for fractures in the adjacent vertebral body of the fixed segment after lumbar fusion fixation.

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 preop 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.

Diagnosis, Risk Factors, and Management of Sacral and Pelvic Fractures After Instrumented Lumbar Fusions: A Systematic Review

STUDY DESIGN

Systematic literature review.

OBJECTIVES

To evaluate risk factors, diagnosis, and management of sacral and pelvic fractures (SPFs) after instrumented fusions.

METHODS

A systematic review following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed using the PubMed database. Articles with patients with an SPF after a lumbar instrumented fusion were included. The articles addressing specifically proximal junctional kyphosis were excluded. Eleven small cases series (level of evidence IV) were reviewed.

RESULTS

The incidence of SPF was 1.86% in one study. The risk factors reported were elderly patients, multilevel surgery, long fusions stopping at L5 or S1 instead of the ilium, osteoporosis, obesity, and sagittal imbalance. Computed tomography scan was the preferential image modality for diagnosing. Nonsurgical treatment may be used in patients with tolerable pain and nondisplaced fracture. Persistent pain was an indication for surgery, as well as fracture displacement. The most common surgical treatment reported was an extension of the fusion to the iliac using iliac screws.

CONCLUSION

SPFs after lumbar instrumented fusion are rare but clinically meaningful complications. The risk factors, diagnosis, and management of SPFs are described in our review.

Percutaneous Endoscopic Lumbar Foraminotomy for Foraminal Stenosis with Postlaminectomy Syndrome in Geriatric Patients

INTRODUCTION

Postlaminectomy syndrome (PLS) or failed back surgery syndrome is a condition characterized by persistent pain following a back surgery. Degenerative processes may result in foraminal stenosis development over time, even after a successful surgery. Percutaneous endoscopic lumbar foraminotomy (PELF) offers a minimally invasive means of treating foraminal stenosis after a back surgery. The objective of this study was to evaluate the outcomes of PELF for foraminal stenosis with PLS in geriatric patients.

METHODS

Two-year follow-up data were collected from 21 consecutive patients aged 65 years or older (mean age, 72.4 years) who underwent PELF for foraminal stenosis with PLS. Transforaminal endoscopic foraminal decompression was performed under local anesthesia. Outcomes were assessed using visual analog scale pain score, Oswestry Disability Index, and modified Macnab criteria.

RESULTS

Mean visual analog scale for leg pain improved from 8.48 at baseline to 3.33 at 6 weeks, 2.10 at 1 year, and 2.19 at 2 years after PELF (P < 0.01). Mean Oswestry Disability Index improved from 67.29 at baseline to 30.69 at 6 weeks, 22.50 at 1 year, and 20.81 at 2 years after PELF (P < 0.01). Based on the modified Macnab criteria, excellent or good results were obtained in 81.0% of patients and symptomatic improvements were obtained in 95.2% of patients.

CONCLUSIONS

The transforaminal endoscopic approach can provide a better access angle to achieve a sophisticated foraminal decompression with less facet and dural injury. Therefore, PELF under local anesthesia can be useful for PLS or postoperative foraminal stenosis in elderly patients.

Oblique lumbar interbody fusion for adjacent segment disease after posterior lumbar fusion: a case-controlled study

Background

This study assessed clinical and radiographic outcomes of oblique lumbar interbody fusion (OLIF) in comparison with posterior reoperation for adjacent segment disease (ASD).

Methods

A total of 26 patients with symptomatic ASD after lumbar fusion were included in this retrospective case-controlled study conducted from January 2013 to December 2018. Twelve patients underwent single-segment OLIF with or without posterior instrumentation (OLIF group), whereas 14 patients underwent posterior reoperation (posterior approach group). The clinical outcomes included operative time, blood loss, hospital stay, Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), and complications. Preoperative and postoperative radiographic outcomes were compared.

Results

The operative time (60.6 ± 16.1 min vs. 150.9 ± 28.5 min, respectively; P < 0.05) and the blood loss in the OLIF group 89.2 ± 49.0 ml vs. 340.7 ± 130.2 ml, respectively; P < 0.05) were significantly lower than those in the posterior group. The hospital stay was lower in the OLIF group than in the posterior approach group (6.6 ± 1.3 days vs. 9.5 ± 2.5 days, respectively; P < 0.05). In the posterior approach group, 6 of 14 patients (42.8%) had issue with dural tear, while none in the OLIF group had such issue (P < 0.05). The ODI score (13.2 ± 4.2 vs. 19.2 ± 7.2, respectively; P = 0.014) and the VAS back pain score were lower in the OLIF group postoperatively and at last follow-up. In the OLIF group, the radiographic outcomes were significantly improved postoperatively.

Conclusions

Due to our results and early experiences, we proposed that OLIF was safe and effective for ASD. Compared with posterior reoperation, OLIF results in shorter operative time and hospital stay, lesser blood loss, and lower risk of dural injury.

Paraspinal Lean Muscle Mass Measurement Using Spine MRI as a Predictor of Adjacent Segment Disease After Lumbar Fusion: A Propensity Score-Matched Case-Control Analysis

OBJECTIVE. The purpose of this study was to compare paraspinal muscle mass between patients with and without adjacent segment disease (ASD) after lumbar fusion. MATERIALS AND METHODS. Fifty patients with ASD (mean age, 61.4 years; ratio of male to female patients: 13:37; mean body mass index [BMI; weight in kilograms divided by the square of height in meters], 25.1) were matched to 50 control patients on the basis of age, sex, BMI, and fusion segment. The total cross-sectional area (CSA) and functional CSA (FCSA; i.e., the area containing lean muscle tissue only) of the paraspinal muscle group (the multifidus and erector spinae muscles) and the psoas muscles were measured on preoperative MRI. The ratio of the FCSA to the total CSA and the skeletal muscle index (SMI; calculated as muscle area [expressed as centimeters squared] divided by the square of the patient's height in meters]) were calculated and compared between the two groups with use of the independent-sample t test. RESULTS. The mean FCSA (2178.6 mm² vs 2594.0 mm²; p = 0.004), the ratio of the FCSA to the total CSA (45.4% vs 52.2%; p = 0.001), and the SMI of the FCSA (8.8 vs 10.6; p = 0.001) of the paraspinal muscle group were significantly smaller in patients with ASD compared to the control group. When the paraspinal and psoas muscle groups were combined, the mean FCSA (3680.8 mm² vs 4268.2 mm²; p = 0.013), the ratio of FCSA to total CSA (53.3% vs 58.6%; p = 0.004), the SMI of the total CSA (27.7 vs 29.3; p = 0.049), and the SMI of the FCSA (14.9 vs 17.3; p = 0.002) were significantly lower in patients with ASD than in control patients. CONCLUSION. Patients with ASD had smaller lean muscle mass (FCSA), a lower ratio of FCSA to total CSA, and a lower SMI of the FCSA of the paraspinal muscle group on pre-operative MRI, compared with control patients.

Biomechanical study of proximal adjacent segment degeneration after posterior lumbar interbody fusion and fixation: a finite element analysis

Purpose

To investigate the biomechanical changes in the proximal adjacent segment with different grades of degeneration after posterior lumbar interbody fusion (PLIF).

Methods

We created three finite element models of the L3–5 with different grades of degeneration (healthy, mild, and moderate) at the L3–4 that were developed by changing the disc height and material properties of the nucleus pulposus. The L4–5 were operated by interbody fusion cages and pedicle screws. All models were loaded with a compressive pre-load of 400 N and a bending moment of 10 N a in three planes to recreate flexion, extension, lateral bending, and axial rotation. The range of motion (ROM), nucleus pressure, and annulus fibrosus pressure of the L3–4 were evaluated.

Results

The ROM, nucleus pressure, and annulus fibrosus pressure increased at the L3–4 after PLIF. As the degeneration progressed in the L3–4, the ROM of the L3–4 decreased while the nucleus pressure and annulus fibrosus pressure increased.

Conclusions

Adjacent segment degeneration (ASD) may be related to the ROM and intradiscal pressure after PLIF. However, as the degeneration of the proximal adjacent segment increases, the ROM in the proximal adjacent segment gradually decreases, but the pressure on the nucleus pulposus and annulus fibrosus gradually increases. Degeneration of the proximal adjacent segment before operation is a risk factor for the ASD after PLIF.

Biomechanical evaluation of lumbar lateral interbody fusion for the treatment of adjacent segment disease

BACKGROUND CONTEXT

Adjacent segment disease (ASD) is a well-known complication after lumbar fusion. Lumbar lateral interbody fusion (LLIF) may provide an alternative method of treatment for ASD while avoiding the morbidity associated with revision surgery through a traditional posterior approach. This is the first biomechanical study to evaluate the stability of lateral-based constructs for treating ASD in existing multilevel fusion model.

PURPOSE

We aimed to evaluate the biomechanical stability of anterior column reconstruction through the less invasive lateral-based interbody techniques compared with traditional posterior spinal fusion for the treatment of ASD in existing multilevel fusion.

STUDY DESIGN/SETTING

Cadaveric biomechanical study of laterally based interbody strategies for treating ASD.

METHODS

Eighteen fresh-frozen cadaveric specimens were nondestructively loaded in flexion, extension, and lateral bending. The specimens were randomized into three different groups according to planned posterior spinal instrumented fusion (PSF): group 1: L5-S1, group 2: L4-S1, and group 3: L3-S1. In each group, ASD was considered the level cranial to the upper-instrumented vertebrae (UIV). After testing the intact spine, each specimen underwent PSF representing prior fusion in the ASD model. The adjacent segment for each specimen then underwent (1) Stand-alone LLIF, (2) LLIF + plate, (3) LLIF + single screw rod (SSR) anterior instrumentation, and (4) LLIF + traditional posterior extension of PSF. In all conditions, three-dimensional kinematics were tracked, and range of motion (ROM) was calculated for the comparisons.

RESULTS

ROM results were expressed as a percentage of the intact spine ROM. LLIF effectively reduces ROM in all planes of ROM. Supplementation of LLIF with plate or SSR provides further stability as compared with stand-alone LLIF. Expansion of posterior instrumentation provides the most substantial stability in all planes of ROM (p <.05). All constructs demonstrated a consistent trend of reduction in ROM between all the groups in all bending motions.

CONCLUSIONS

This biomechanical study suggests potential promise in exploring LLIF as an alternative treatment of ASD but reinforces previous studies' findings that traditional expansion of posterior instrumentation provides the most biomechanically stable construct.

Adjacent Segment Disease After Single Segment Posterior Lumbar Interbody Fusion for Degenerative Spondylolisthesis: Minimum 10 Years Follow-up

STUDY DESIGN

A retrospective study.

OBJECTIVE

The aim of this study was to investigate the incidence of adjacent segment disease (ASD) at 2, 5, and 10 years after primary posterior lumbar interbody fusion (PLIF), and clinical features of ASD.

SUMMARY OF BACKGROUND DATA

Few reports have examined ASD after PLIF with more than 10 years of follow-up. Furthermore, no reports have examined limited conditions of preoperative pathology, fusion segment, and fusion method with long follow-up.

METHODS

Data were reviewed for 128 patients who underwent single-segment PLIF for L4 degenerative spondylolisthesis and could be followed for at least 10 years. Mean age at the time of surgery was 63 years, and mean follow-up was 12.4 years. Follow-up rate was 62.4%. ASD was defined as radiological ASD (R-ASD), radiological degeneration adjacent to the fusion segment by plain X-rays and magnetic resonance imaging (MRI); symptomatic ASD (S-ASD), a symptomatic condition due to neurological deterioration at the adjacent segment degeneration; and operative ASD (O-ASD), S-ASD requiring revision surgery.

RESULTS

Incidences of each ASD at 2, 5, and 10 years after primary PLIF were 19%, 49%, and 75% for R-ASD, 6%, 14%, and 31% for S-ASD, and 5%, 9%, and 15% for O-ASD, respectively. O-ASD incidence was 24% at final follow-up. O-ASD peak was bimodal, at 2 and 10 years after primary PLIF. O-ASD was mainly observed at the cranial segment (77%), followed by the caudal segment (13%) and both cranial and caudal segments (10%). With respect to O-ASD pathology, degenerative spondylolisthesis was observed in 52%, spinal stenosis in 39%, and disc herniation in 10%.

CONCLUSION

Incidences of R-ASD, S-ASD, and O-ASD at 10 years after primary PLIF were 75%, 31%, and 15%, respectively. With respect to O-ASD pathology, degenerative spondylolisthesis at the cranial segment was the most frequent.

LEVEL OF EVIDENCE

4.

Endoscope-Assisted Anterior Lumbar Interbody Fusion with Computed Tomography-Guided, Image-Navigated Unilateral Cortical Bone Trajectory Screw Fixation in Managing Adjacent Segment Disease in L5/S1: Technical Note

OBJECTIVE

We sought to describe a novel technique in managing a patient with adjacent segment disease at the L5/S1 level.

METHODS

We performed an endoscope-assisted anterior lumbar interbody fusion with computed tomography-guided, image-navigated unilateral cortical bone trajectory screw fixation to treat L5/S1 intervertebral disk pathology.

RESULTS

Patient was successfully treated by a direct endoscopic decompression through the anterior access, interbody fusion using an anterior lumbar interbody fusion cage, unilateral cortical bone trajectory instrumentation under computed tomography-guided image navigation.

CONCLUSIONS

This minimally invasive technique is effective in terms of decompression and fixation. It could be used as an alternative method to treat patients with L5/S1 adjacent segment disease.

Minimally invasive decompression in patients with degenerative spondylolisthesis associated with lumbar spinal stenosis. Report of a surgical series and review of the literature

We reported the results of minimally invasive spinal decompression (MISD) in patients with degenerative spondylolisthesis (DS) associated with lumbar spinal stenosis (LSS) and performed a literature review in order to evaluate the clinical and radiological outcomes, the complications and reoperation rate of MISD procedures in these patients. Data of 28 patients submitted to MISD for DS associated to LSS were reviewed. We evaluated the Visual Analogue Scale (VAS) both for low back pain (LBP) and legs pain, the Oswestry Disability Index (ODI) and the degree of the slippage. A PubMed search of the English literature was conducted. Only papers with more than 10 patients and reporting explicitly data of patients with DS were included in the analysis. We found a statistically significant improvement of LBP, legs pain and ODI in our series. The degree of slippage was stable at follow-up (FU) with no need of reoperation. No major complications occurred. In our literature review, we were able to analyze the differences in ODI in 156 patients and the differences in Japanese Orthopedic Association (JOA) score in 218 patients. We observed a statistically significant improvement of ODI and JOA score at FU compared to pre-operative. The percentage of slippage, evaluated in 283 patients, was unchanged at FU compared to pre-operative. The overall complication rate was 1.6%. The overall reoperation rate was 4.5%. MISD procedures are safe and effective in patients with DS associated to LSS and are associated to low morbidity and significant improvement of disability without progression of slippage.

The influence of spinopelvic parameters on adjacent-segment degeneration after short spinal fusion for degenerative spondylolisthesis

OBJECTIVE

Spinopelvic parameters, such as the pelvic incidence (PI) angle, sacral slope angle, and pelvic tilt angle, are important anatomical indices for determining the sagittal curvature of the spine and the individual variability of the lumbar lordosis (LL) curve. The aim of this study was to investigate the influence of spinopelvic parameters and LL on adjacent-segment degeneration (ASD) after short lumbar and lumbosacral fusion for single-level degenerative spondylolisthesis.

METHODS

The authors retrospectively reviewed the records of all short lumbar and lumbosacral fusion surgeries performed between August 2003 and July 2010 for single-level degenerative spondylolisthesis in their orthopedic department.

RESULTS

A total of 30 patients (21 women and 9 men, mean age 64 years) with ASD after lower lumbar or lumbosacral fusion surgery comprised the study group. Thirty matched patients (21 women and 9 men, mean age 63 years) without ASD comprised the control group, according to the following matching criteria: same diagnosis on admission, similar pathologic level (≤ 1 level difference), similar sex, and age. The average follow-up was 6.8 years (range 5-8 years). The spinopelvic parameters had no significant influence on ASD after short spinal fusion.

CONCLUSIONS

Neither the spinopelvic parameters nor a mismatch of PI and LL were significant factors responsible for ASD after short spinal fusion due to single-level degenerative spondylolisthesis.

Bone SPECT/CT in Postoperative Spine

Back pain is a common problem and the diagnosis and treatment depend on the clinical presentation, yet overlap between pain syndromes is common. Imaging of patients with chronic back pain in both pre- and postoperative scenarios include radiological, radionuclide, and hybrid techniques. In general, these techniques have their own advantages and limitations. The aim of surgery is to eliminate pathologic segmental motion and accompanying symptoms, especially pain. However, surgical procedures are not without complications and localizing the cause of the pain is often challenging. Radiobisphosphonate bone SPECT/CT is reported to be useful in evaluating benign orthopedic conditions and it often provides valuable information such as accurate localization and characterization of bone abnormalities. In this review, routinely used spinal surgical techniques and procedures are discussed, as well as the acute and delayed complications related to spinal surgery, the role of conventional imaging, and the potential uses of radionuclide bone SPECT/CT to diagnose pseudoarthrosis, cage subsidence, loosening and misalignment, hardware failure, and postoperative infection.

Stand-Alone Anterolateral Interbody Fusion Versus Extended Posterior Fusion for Symptomatic Adjacent-Segment Degeneration: A Retrospective Study of 2 Years' Follow-up

OBJECTIVE

To evaluate the clinical and radiologic outcome of stand-alone anterolateral lumbar interbody fusion (ALLIF) using self-locked cages in comparison with extended posterior lumbar interbody fusion (PLIF) for symptomatic adjacent-segment degeneration (ASD) after posterior lumbar fusion.

METHODS

This retrospective study enrolled 40 symptomatic patients with ASD who were treated with ALLIF (n = 13) or extended PLIF (n = 27) between January 2011 and January 2015. Evaluations were performed preoperatively, at 3, 12, and 24 months postoperatively. Clinical outcome measurements included visual analog scale scores for low-back and leg pain, Oswestry Disability Index score for function assessment, Short-Form 36 Questionnaire for quality of life, and modified Macnab criteria for patient satisfaction. Radiologic outcome measurements included fusion rate, cage subsidence, disc height, and lumbar lordosis.

RESULTS

There were no significant differences in the baseline data for the ALLIF and PLIF groups (P > 0.05). Mean operative time, blood loss, and length of hospital stay were significantly decreased for the ALLIF group (P < 0.05). Postoperatively, low back and leg pain was relieved, function and quality of life were improved in both groups (P < 0.05), whereas disc height and lumbar lordosis were restored (P < 0.05). At 24-month follow-up, fusion was observed in 13 of 13 patients (100%), with 3 of 13 (23.1%) patients developing cage subsidence in the ALLIF group.

CONCLUSIONS

Stand-alone ALLIF could achieve satisfactory safety and efficacy for the treatment of symptomatic ASD with less trauma and faster recovery, and it may serve as an alternative surgical treatment for symptomatic ASD with appropriate indication.

Use of the "dual construct" for the management of complex spinal reconstructions

BACKGROUND CONTEXT

Surgical management of complex spinal reconstructions remains a clinical challenge, as pseudoarthrosis with subsequent rod breakage can occur. Increased rod density in the form of "satellite" or "outrigger" rods have been described; however, rod-fracture above or below satellite rods persist and can result in dissociation of the construct, loss of correction, and recurrence of deformity. The use of four distinct and mechanically independent rods (dual construct) reduces this concern. Since the original case description in 2006, there have been no other studies that use the dual construct for the surgical management of complex spinal reconstructions.

PURPOSE

The purpose of this study is to review the long-term experience and surgical technique using the dual construct, and to present our complications, rod fracture rates, and outcomes for the surgical management of complex spinal reconstructions.

STUDY DESIGN

This study used a surgical technique with case series outcomes.

PATIENT SAMPLE

Patients were from a single-institute who underwent dual construct between 2010 and 2014 and who were available for 2-year follow-up.

OUTCOME MEASURES

Radiographic and functional outcomes, complications, rod fracture rates, and revision surgery rates were the outcome measures.

METHODS

A retrospective review was conducted from a single institution between 2010 and 2014, with a subsequent 2-year follow-up period. Extensive review of patients' medical record, radiographs, and advanced imaging where available was performed. Medical record was evaluated for patient demographics, surgical procedure, and complications. Radiographic measurements included presence or absence of implant failure and proximal junctional kyphosis or distal junctional kyphosis.

RESULTS

A total of 36 patients underwent surgical reconstruction. The average estimated blood loss was 1,856 cc (range, 400-4,000 cc). The average length of stay was 7.3 days (range, 4-22 days). Clinical follow-up reported 21 patients (58.3%) with no or minimal pain. There were six deaths during the follow-up unrelated to the index procedure. Radiographic follow-up revealed three patients (8.3%) with rod fracture; one patient with one rod fracture, and two patients with two rod fractures. No patient had three or all four rod fractures. There were no screw fractures. None of the patients with rod fractures required revision surgery.

CONCLUSIONS

The biggest advantage of the dual construct is that rod breakage, although uncommon, is typically minimal, or asymptomatic, and more importantly does not result in loss of alignment, and therefore has not required revision surgery. The dual construct approach is a safe alternative to traditional two-rod constructs, with encouraging outcomes at follow-up.

Effectiveness of Reoperations for Adjacent Segment Disease Following Lumbar Spinal Fusion

Although several options are available to address adjacent segment disease (ASD), the most effective surgical treatment has not been determined. In addition, it is important to subdivide ASD into stenosis with or without instability to determine if a decompression alone vs an extension of fusion is necessary. A systematic search of multiple medical reference databases was conducted for studies on surgical treatment of ASD. The primary outcome measures used were radiographic and clinical success rates. Meta-analysis was completed to determine effect summary values, 95% confidence intervals, and Q statistic and I² values, using the random effects model for heterogeneity. The search yielded 662 studies, of which 657 were excluded. A total of 5 (level IV) studies with a total of 118 patients were included in this review. In 2 studies (46 patients), stenosis without instability was the indication for reoperation for ASD. However, extension of fusion was the modality of choice for the treatment of ASD in all studies. Overall clinical improvement (in back and/or leg pain scores) was noted in 71.3% of patients (95% confidence interval, 37.4-100), while radiographic fusion was noted in 89.3% of patients (95% confidence interval, 51.2-100). Following reoperation for ASD, revision surgery rates ranged from 4.5% to 23.1% at last clinical follow-up. There is variability in the clinical improvement following lumbar fusion for ASD. In addition, little literature exists regarding the optimal treatment options for patients with ASD for stenosis with or without instability. [Orthopedics. 2018; 41(2):e161-e167.].

Treatment of low back pain elicited by superior cluneal nerve entrapment neuropathy after lumbar fusion surgery

Object

Low back pain (LBP) attributable to fusion failure, implant failure, infection, malalignment, or adjacent segment disease may persist after lumbar fusion surgery (LFS). Superior cluneal nerve (SCN) entrapment neuropathy (SCNEN) is a clinical entity that can produce LBP. We report that SCNEN treatment improved LBP in patients who had undergone LFS.

Methods

Between April 2012 and August 2015, we treated 8 patients (4 men and 4 women ranging in age from 38 to 88 years; mean age, 69 years) with SCNEN for their LBP after LFS. Our criteria for the diagnosis of SCNEN included a trigger point over the posterior iliac crest 7 cm from the midline and numbness and radiating pain in the SCN area upon compression of the trigger point. Symptom relief was obtained in more than 75% of patients within 2 h of inducing a local nerve block at the trigger point in the buttocks. The mean postoperative follow-up period was 28 months (range, 9-54 months).

Results

LBP was unilateral in 3 and bilateral in 5 patients. The senior author (T.I.) operated all patients for SCNEN under local anesthesia because they reported recurrence of pain after the analgesic effect of repeat injections wore off. This led to a significant improvement of their LBP.

Conclusions

SCNEN should be considered in patients reporting LBP after LFS. Treatment of SCNEN may be a useful option in patients with failed back surgery syndrome after LFS.

Lateral Lumbar Interbody Fusion and in Situ Screw Fixation for Rostral Adjacent Segment Stenosis of the Lumbar Spine

Objective

The purpose of this study is to describe the detailed surgical technique and short-term clinical and radiological outcomes of lateral lumbar interbody fusion (LLIF) and in situ lateral screw fixation using a conventional minimally invasive screw fixation system (MISF) for revision surgery to treat rostral lumbar adjacent segment disease.

Methods

The medical and radiological records were retrospectively reviewed. The surgery was indicated in 10 consecutive patients with rostral adjacent segment stenosis and instability. After the insertion of the interbody cage, lateral screws were inserted into the cranial and caudal vertebra using the MISF through the same LLIF trajectory. The radiological and clinical outcomes were assessed preoperatively and at 1, 3, 6, and 12 months postoperatively.

Results

The median follow-up period was 13 months (range, 3–48 months). Transient sensory changes in the left anterior thigh occurred in 3 patients, and 1 patient experienced subjective weakness; however, these symptoms normalized within 1 week. Back and leg pain were significantly improved (p<0.05). In the radiological analysis, both the segmental angle at the operated segment and anterior disc height were significantly increased. At 6 months postoperatively, solid bony fusion was confirmed in 7 patients. Subsidence and mechanical failure did not occur in any patients.

Conclusion

This study demonstrates that LLIF and in situ lateral screw fixation may be an alternative surgical option for rostral lumbar adjacent segment disease.

Bone SPECT/CT in the postoperative spine: a focus on spinal fusion

Low back pain is a global problem affecting one in 10 people. The management of low back pain varies from conservative to more invasive methods with a spectacular increase in the number of patients undergoing spinal fusion surgery during the last decade. Conventional radiological and radionuclide studies are often used in the assessment of persistent or recurring pain after spinal surgery with several advantages and limitations related to each technique. This article reviews the key contribution of integrated bone SPECT/CT in evaluating patients with persistent or recurring pain after spinal surgery, focusing on spinal fusion. Current literature supports the use of bone SPECT/CT as an adjunct imaging modality and problem-solving tool in evaluating patients with suspicion of pseudarthrosis, adjacent segment degeneration, and hardware failure. The role of bone SPECT/CT in post-operative orthopaedic scenarios is evolving, and this review highlights the need for further research on the role of bone SPECT/CT in these patients.

Could the Topping-Off Technique Be the Preventive Strategy against Adjacent Segment Disease after Pedicle Screw-Based Fusion in Lumbar Degenerative Diseases? A Systematic Review

The "topping-off" technique is a new concept applying dynamic or less rigid fixation such as hybrid stabilization device (HSD) or interspinous process device (IPD) for the purpose of avoiding adjacent segment disease (ASD) proximal to the fusion construct. A systematic review of the literature was performed on the effect of topping-off techniques to prevent or decrease the occurrence of ASD after lumbar fusion surgery. We searched through major online databases, PubMed and MEDLINE, using key words related to "topping-off" technique. We reviewed the surgical results of "topping-off" techniques with either HSD or IPD, including the incidence of ASD at two proximal adjacent levels (index and supra-adjacent level) as compared to the fusion alone group. The results showed that the fusion alone group had statistically higher incidence of radiographic (52.6%) and symptomatic (11.6%) ASD at the index level as well as higher incidence (8.1%) of revision surgery. Besides, the HSD (10.5%) and fusion groups (24.7%) had statistically higher incidences of radiographic ASD at supra-adjacent level than the IPD (1%). The findings suggest that the "topping-off" technique may potentially decrease the occurrence of ASD at the proximal motion segments. However, higher quality prospective randomized trials are required prior to wide clinical application.

Capsulated Metallic Debris Tumor Mass Mimicking Adjacent Segment Disease: A Case Report

STUDY DESIGN

A case report.

OBJECTIVE

To inform the spine surgeons another cause of late complications after instrumented spinal fusion surgery.

SUMMARY OF BACKGROUND DATA

Posterior lumbar instrumented fusion has been widely applied as an effective procedure for treating patients with degenerative lumbar spine disease. The development of pathology at the mobile segment adjacent to the lumbar spinal fusion has been termed as adjacent segment disease.

METHODS

Most patients with adjacent segment disease present with recurrent back pain, sciatica, intermittent claudication, or even muscle weakness. Herein, we report the case of a 58-year-old man with posterior lumbar instrumented fusion at L4-L5 who complained of recurrent neurological symptoms mimicking adjacent instability and stenosis. In addition to severe adjacent stenosis at L3-L4, preoperative magnetic resonance imaging showed an intraspinal extradural tumor-like mass with compression of the neurological elements.

RESULTS

The well-capsulated tumor mass was gently dissected and meticulously excised without injury to the adhesive dura or nerve roots. The tumor specimen was fixed in formalin, and then decalcified and tinted using several special stains, which conformed metallic wear debris, resulting in foreign body reaction.

CONCLUSIONS

The metallic wear particulates may initiate a cascade of immune and inflammatory responses. Therefore, attention should be paid to patients who are found to have loosening of the implants at the metal-metal or metal-bone interface.

Cost-effectiveness Analysis of Existing Pedicle Screws Reusing Technique in Extension Revision Operation for Adjacent Segmental Stenosis After Lumbar Posterolateral Fusion

STUDY DESIGN

Retrospective case-control study.

OBJECTIVE

A cost-effectiveness analysis was performed by comparing patients who received extension revision operations for adjacent segment disease (ASD) reusing the pedicle screws extracted from fused segments with patients who received conventional surgery.

SUMMARY OF BACKGROUND DATA

ASD often required extension revision surgery, and during extension surgery, pedicle screws may be reused by extracting from the fused segments of primary surgery.

METHODS

Study examined 37 patients who received extension revision surgery for ASD from January 2003 to December 2013. For the fixation of extended segments during revision operation, in 16 cases the pedicle screws extracted from fused segments were reused (group R), and in 21 cases new pedicle screws were used (group C) as a conventional method. Clinical outcomes were evaluated by means of visual analog scale scores for lumbago and leg pain, and the Korean Oswestry Disability Index. Radiologic outcomes were evaluated from the extent of bone union. The total operating costs in the two groups were compared.

RESULTS

Visual analog scale scores for lumbago and leg pain, and the Korean Oswestry Disability Index measured at final follow-up averaged 3.6 and 3.8, and 19.9 in group R, and 3.8 and 3.1, and 21.1 in group C, respectively (P = 0.280, P = 0.387, P = 0.751). For radiologic outcomes, there was one case of nonunion in each group. The cost of surgery was 5332 US dollars in group R, and 6109 US dollars in group C, respectively (P = 0.036).

CONCLUSION

Reusing pedicle screws extracted from the fused segments during extension revision operation for ASD can reduce the cost of surgery, and achieves clinical and radiological results similar to those of the conventional operation.

LEVEL OF EVIDENCE

4.

Clinical Experiences of Non-fusion Dynamic Stabilization Surgery for Adjacent Segmental Pathology after Lumbar Fusion

BACKGROUND

As an alternative to spinal fusion, non-fusion dynamic stabilization surgery has been developed, showing good clinical outcomes. In the present study, we introduce our surgical series, which involves non-fusion dynamic stabilization surgery for adjacent segment pathology (ASP) after lumbar fusion surgery.

METHODS

Fifteen patients (13 female and 2 male, mean age of 62.1 years) who underwent dynamic stabilization surgery for symptomatic ASP were included and medical records, magnetic resonance images (MRI), and plain radiographs were retrospectively evaluated.

RESULTS

Twelve of the 15 patients had the fusion segment at L4-5, and the most common segment affected by ASP was L3-4. The time interval between prior fusion and later non-fusion surgery was mean 67.0 months. The Visual Analog Scale and Oswestry Disability Index showed values of 7.4 and 58.5% before the non-fusion surgery and these values respectively declined to 4.2 and 41.3% postoperatively at 36 months (p=0.027 and p=0.018, respectively). During the mean 44.8 months of follow-up, medication of analgesics was also significantly reduced. The MRI grade for disc and central stenosis identified significant degeneration at L3-4, and similar disc degeneration from lateral radiographs was determined at L3-4 between before the prior fusion surgery and the later non-fusion surgery. After the non-fusion surgery, the L3-4 segment and the proximal segment of L2-3 were preserved in the disc, stenosis and facet joint whereas L1-2 showed disc degeneration on the last MRI (p=0.032). Five instances of radiologic ASP were identified, showing characteristic disc-space narrowing at the proximal segments of L1-2 and L2-3. However, no patient underwent additional surgery for ASP after non-fusion dynamic stabilization surgery.

CONCLUSION

The proposed non-fusion dynamic stabilization system could be an effective surgical treatment for elderly patients with symptomatic ASP after lumbar fusion.

Impact of Instrumented Spinal Fusion on the Development of Vertebral Compression Fracture

Instrumented spinal fusion has become one of the most common surgeries for patients with various spinal disorders. Only few studies have reported subsequent vertebral compression fractures (VCFs) after instrumented spinal fusion. The purpose of this study was to evaluate the risk of new VCFs in patients undergoing instrumented spinal fusion.We obtained claims data from the National Health Insurance Research Database of Taiwan and retrospectively reviewed 6949 patients with instrumented spinal fusion as the spinal fusion cohort. Control subjects were individually matched at a ratio of 10:1 with those of the spinal fusion cohort according to age, sex, and the index day. Comorbidities were classified as those existing before the index day, and these included diabetes mellitus, hypertension, osteoporosis, and cerebrovascular accident. The end of the follow-up period for the analyses was marked on the day new VCFs developed, enrolment in the National Health Insurance was terminated, on the day of death, or until the end of 2012. We used the Cox proportion hazards model to analyze the hazard ratio (HR) for developing new VCFs.Patients with instrumented spinal fusion were significantly more likely to develop new VCFs (1.87% vs .25%, HR: 8.56; P < 0.001). Female, elderly, and osteoporotic patients had a high incidence of new VCFs after spinal fusion. The HR for developing new VCFs after instrumented spinal fusion was higher in patients younger than 65 years than in those 65 years or older (HR: 10.61 vs 8.09). Male patients with instrumented spinal fusion also had a higher HR of developing new VCFs than female patients (men, HR: 26.42; women, HR: 7.53).In our retrospective cohort study, patients who had undergone instrumented spinal fusion surgery exhibited an increased risk of developing new VCFs. Particularly, the HR increased in young (age <65 years) and male patients.

Cell Therapy Using Bone Marrow-Derived Stem Cell Overexpressing BMP-7 for Degenerative Discs in a Rat Tail Disc Model

Degenerative discs can cause low back pain. Cell-based transplantation or growth factors therapy have been suggested as a strategy to stimulate disc regeneration. Bone marrow-derived mesenchymal stem cells (BMDMSC) containing bone morphogenetic protein-7 (BMP-7) gene were constructed. We evaluated the effectiveness of these BMP-7 overexpressing cells on degenerative discs in rat tails. In vitro and in vivo studies were designed. In the first stage, the rats were divided into two group according to discs punctured by different needle gauges (18 gauge and 22 gauge). In the second stage, the ideal size of needle was used to induce rat tail disc degeneration. These animals are divided into three groups according to timing of treatment (zero-week, two-week, four-week). Each group was divided into three treating subgroups: control group, BMDMSC group, and Baculo-BMP-7-BMDMSC group. Each rat undergoes radiography examination every two weeks. After eight weeks, the discs were histologically examined with hematoxylin and eosin stain and Alcian blue stain. The 18-gauge group exhibited significant decrease in disc height index (%) than 22-gauge group at eight weeks at both Co6-7 (58.1% ± 2.8% vs. 63.7% ± 1.0%, p = 0.020) and Co8-9 discs (62.7% ± 2.8% vs. 62.8% ± 1.5%, p = 0.010). Baculo-BMP-7-BMDMSCs group showed significant difference in disc height index compared to the BMDMSCs group at both Co6-7 (93.7% ± 1.5% vs. 84.8% ± 1.0%, p = 0.011) and Co8-9 (86.0% ± 2.1% vs. 81.8% ± 1.7%, p = 0.012). In Baculo-BMP-7-BMDMSCs group, the zero-week treatment subgroup showed significant better in disc height index compared to two-week treatment group (p = 0.044), and four-week treatment group (p = 0.011). The zero-week treatment subgroup in Baculo-BMP-7-BMDMSCs group also had significant lower histology score than two-week treatment (4.3 vs. 5.7, p = 0.045) and four-week treatment (4.3 vs. 6.0, p = 0.031). In conclusion, Baculo-BMP-7-BMDMSC can slow down the progression of disc degeneration, but could not provide evidence of regeneration. Early treatment might obtain more distinct results.

Impact of lumbar instrumented circumferential fusion on the development of adjacent vertebral compression fracture

We evaluated the impact of lumbar instrumented circumferential fusion on the development of adjacent level vertebral compression fractures (VCFs). Instrumented posterior lumbar interbody fusion (PLIF) has become a popular procedure for degenerative lumbar spine disease. The immediate rigidity produced by PLIF may cause more stress and lead to greater risk of adjacent VCFs. However, few studies have investigated the relationship between PLIF and the development of subsequent adjacent level VCFs. Between January 2005 and December 2009, a total of 1936 patients were enrolled. Of these 224 patients had a new VCF and the incidence was statistically analysed with other covariants. In total 150 (11.1%) of 1348 patients developed new VCFs with PLIF, with 108 (72%) cases at adjacent segment. Of 588 patients, 74 (12.5%) developed new subsequent VCFs with conventional posterolateral fusion (PLF), with 37 (50%) patients at an adjacent level. Short-segment fusion, female and age older than 65 years also increased the development of new adjacent VCFs in patients undergoing PLIF. In the osteoporotic patient, more rigid fusion and a higher stress gradient after PLIF will cause a higher adjacent VCF rate.

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.