Extreme lateral interbody fusion provides minimally invasive treatment of spinal deformity, but complications including nerve and psoas muscle injury have been noted. To avoid nerve injury, mini-open anterior retroperitoneal lumbar interbody fusion methods using an approach between the aorta and psoas, such as oblique lumbar interbody fusion (OLIF) have been applied. OLIF with percutaneous pedicle screws without posterior decompression can indirectly decompress the spinal canal in lumbar degenerated spondylolisthesis. In the current study, we examined the radiographic and clinical efficacy of OLIF for lumbar degenerated spondylolisthesis.
Methods
We assessed 20 patients with lumbar degenerated spondylolisthesis who underwent OLIF and percutaneous pedicle screw fixation without posterior laminectomy. MR and CT images and clinical symptoms were evaluated before and 6 months after surgery. Cross sections of the spinal canal were evaluated with MRI, and disk height, cross-sectional areas of intervertebral foramina, and degree of upper vertebral slip were evaluated with CT. Clinical symptoms including low back pain, leg pain, and lower extremity numbness were evaluated using a visual analog scale and the Oswestry Disability Index before and 6 months after surgery.
Results
After surgery, significant increases in axial and sagittal spinal canal diameter (12 and 32 %), spinal canal area (19 %), disk height (61 %), and intervertebral foramen areas (21 % on the right side, 39 % on the left), and significant decrease of upper vertebral slip (?9 %) were found (P < 0.05). Low back pain, leg pain, and lower extremity numbness were significantly reduced compared with before surgery (P < 0.05).
Conclusions
Significant improvements in disk height and spinal canal area were found after surgery. Bulging of disks was reduced through correction, and stretching the yellow ligament may have decompressed the spinal canal. Lumbar anterolateral fusion without laminectomy may be useful for lumbar spondylolisthesis with back and leg symptoms.
The most effective interbody fusion technique for degenerative disk disease (DDD) is still controversial. The purpose of our study is to compare pure lateral (LLIF) and oblique lateral (OLIF) approaches for the treatment of lumbar DDD from L1–L2 to L4–L5, in terms of clinical and radiological outcomes.
Materials and methods
45 patients underwent lumbar interbody fusion for pure lumbar DDD from L1–L2 to L4–L5 through LLIF (n?=?31, mean age 62.1 years, range 45–78 years) or OLIF (n?=?14, mean age 57.4 years, range 47–77 years). Clinical evaluations were performed with ODI and SF-36 tests. Radiological assessment was based on the modification of coronal segmental Cobb angles and segmental lumbar lordosis (L1–S1).
Results
On ODI and SF-36, all patients presented good results at follow-up, with 26% the difference between the LIF and OLIF groups on ODI scale in the post-operative period, and 3.9 and 8.8 points difference on physical and mental SF-36 in favor of OLIF. Radiological parameters improved significantly in both groups. The mean correction was 6.25° for cCobb (11.3° in LIF and 1.9° in OLIF), 2.5° for sLL (2° in LLIF and 4° in OLIF).
Conclusions
LLIF and OLIF represent safe and effective MIS procedures for the treatment of lumbar DDD. LLIF had some risks of motor deficit and monitoring is mandatory, though it addressed more the coronal deformities. OLIF did not imply risks for motor deficits, but attention should be paid to vascular anatomy. It was more effective in kyphotic segmental deformities.
Graphical abstract
These slides can be retrieved under Electronic Supplementary material.
The lateral approach for anterior interbody fusion allows placement of a large footprint intervertebral spacer to indirectly decompress the neural elements through disc height restoration and resultant soft tissue changes. However, it is not well understood under what circumstances indirect decompression in lateral approach surgery is sufficient. This report aimed to evaluate clinical scenarios where indirect decompression was and was not sufficient in symptom resolution when using lateral interbody fusion.
Methods
A prospective study was undertaken of 122 consecutive patients treated with lateral interbody fusion without direct decompression. Pre- and postoperative symptomatology was assessed to evaluate the extent of neural decompression following implantation with a lateral polyetheretherketone spacer. Failure to improve or resolve preoperative radicular pain was considered a failure of indirect decompression and indicated these patients for additional posterior decompressive surgery.
Results
Unplanned second stage decompression was required in 11 patients. Of these patients, 7/11 early in this series had pathology that was underappreciated including spondylolisthesis from high grade facet arthropathy with instability (3), bony lateral recess stenosis (3) and both spondylolisthesis/stenosis (1). Three patients had iatrogenic leg pain through cage misplacement. There was one failure of indirect decompression that could not be explained through retrospective analysis of the patient’s record.
Conclusion
Indirect decompression clearly has a role in minimizing the amount of surgery that is required. However, it is important to consider the circumstances where this technique may be effective and preoperative considerations that may improve patient selection.
Aim of the study was to evaluate the biomechanical stability and the clinical efficacy of a lumbar interbody fusion obtained by single oblique cage implanted by a posterior approach.
Method
Through the realization of three finite element models (FEMs), the biomechanics of POLIF was compared to PLIF and TLIF. Ninety-four patients underwent interbody fusion by POLIF with instrumented posterolateral fusion. Clinical and radiographic outcomes were evaluated at regular intervals for at least 6 months.
Results
The FEMs showed no statistically significant differences in stability in compression and flexion–extension. Mean preoperative VAS score was 7.1, decreased to 2.1 at follow-up. Mean preoperative SF-12 value was 34.5 %, increased to 75.4 % at follow-up. All patients showed a good fusion rate and no hardware failure.
Discussion
POLIF associated to instrumented posterolateral fusion is a viable and safe surgical technique, which ensures a biomechanical stability similar to other surgical techniques.
Expandable cages are a more recent option for maintaining or restoring disc height and segmental lordosis with transforaminal lumbar interbody fusion (TLIF). Complications associated with expandable cages have not yet been widely reported. We report a case of postoperative failure of a polyether-ether-ketone (PEEK) expandable interbody device used during TLIF.
Methods
A 50-year-old man presented with severe back and right leg pain after undergoing L4-5 and L5-S1 TLIFs with expandable cages and L3-S1 posterior instrumented fusion. Imaging showed retropulsion of a portion of the interbody cage into the spinal canal causing nerve compression. Displacement occurred in a delayed manner. In addition, pseudoarthrosis was present.
Results
The patient underwent re-exploration with removal of the retropulsed wafer and redo fusion.
Conclusions
Expandable cages are a recent innovation; as such, efficacy and complication data are limited. As with any new device, there exists potential for mechanical failure, as occurred in the case presented.
Whether compensation for professional services drives the use of those services is an important question that has not been answered in a robust manner. Specifically, there is a growing concern that spine care practitioners may preferentially choose more costly or invasive procedures in a fee-for-service system, irrespective of the underlying lumbar disorder being treated.
Questions/purposes
(1) Were proportions of interbody fusions higher in the fee-for-service setting as opposed to the salaried Department of Defense setting? (2) Were the odds of interbody fusion increased in a fee-for-service setting after controlling for indications for surgery?
Methods
Patients surgically treated for lumbar disc herniation, spinal stenosis, and spondylolisthesis (2006–2014) were identified. Patients were divided into two groups based on whether the surgery was performed in the fee-for-service setting (beneficiaries receive care at a civilian facility with expenses covered by TRICARE insurance) or at a Department of Defense facility (direct care). There were 28,344 patients in the entire study, 21,290 treated in fee-for-service and 7054 treated in Department of Defense facilities. Differences in the rates of fusion-based procedures, discectomy, and decompression between both healthcare settings were assessed using multinomial logistic regression to adjust for differences in case-mix and surgical indication.
Results
TRICARE beneficiaries treated for lumbar spinal disorders in the fee-for-service setting had higher odds of receiving interbody fusions (fee-for-service: 7267 of 21,290 [34%], direct care: 1539 of 7054 [22%], odds ratio [OR]: 1.25 [95% confidence interval 1.20–1.30], p < 0.001). Purchased care patients were more likely to receive interbody fusions for a diagnosis of disc herniation (adjusted OR 2.61 [2.36–2.89], p < 0.001) and for spinal stenosis (adjusted OR 1.39 [1.15–1.69], p < 0.001); however, there was no difference for patients with spondylolisthesis (adjusted OR 0.99 [0.84–1.16], p = 0.86).
Conclusions
The preferential use of interbody fusion procedures was higher in the fee-for-service setting irrespective of the underlying diagnosis. These results speak to the existence of provider inducement within the field of spine surgery. This reality portends poor performance for surgical practices and hospitals in Accountable Care Organizations and bundled payment programs in which provider inducement is allowed to persist.
To evaluate the results of a novel rigid–dynamic stabilization technique in lumbar degenerative segment diseases (DSD), expressly pointing out the preservation of postoperative lumbar lordosis (LL).
Materials and methods
Forty-one patients with one level lumbar DSD and initial disc degeneration at the adjacent level were treated. Circumferential lumbar arthrodesis and posterior hybrid instrumentation were performed to preserve an initial disc degeneration above the segment that has to be fused. Clinical and spino-pelvic parameters were evaluated pre- and postoperatively.
Results
At 2-year follow-up, a significant improvement of clinical outcomes was reported. No statistically significant difference was noted between postoperative and 2-year follow-up in LL and in disc/vertebral body height ratio at the upper adjacent fusion level.
Conclusions
When properly selected, this technique leads to good results. A proper LL should be achieved after any hybrid stabilization to preserve the segment above the fusion.
Discectomy and endplate preparation are important steps in interbody fusion for ensuring sufficient arthrodesis. While modern less-invasive approaches for lumbar interbody fusion have gained in popularity, concerns exist regarding their ability to allow for adequate disc space and endplate preparation. Thus, the purpose of this study was to quantitatively and qualitatively evaluate and compare disc space and endplate preparation achieved with four less-invasive approaches for lumbar interbody fusion in cadaveric spines.
Methods
A total of 24 disc spaces (48 endplates) from L2 to L5 were prepared in eight cadaveric torsos using mini-open anterior lumbar interbody fusion (mini-ALIF), minimally invasive posterior lumbar interbody fusion (MAS PLIF), minimally invasive transforaminal lumbar interbody fusion (MAS TLIF) or minimally invasive lateral, transpsoas interbody fusion (XLIF) on two specimens each, for a total of six levels and 12 endplates prepared per procedure type. Following complete discectomy and endplate preparation, spines were excised and split axially at the interbody disc spaces. Endplates were digitally photographed and evaluated using image analysis software. Area of endplate preparation was measured and qualitative evaluation was also performed to grade the quality of preparation.
Results
The XLIF approach resulted in the greatest relative area of endplate preparation (58.3 %) while mini-ALIF resulted in the lowest at 35.0 %. Overall, there were no differences in percentage of preparation between cranial and caudal endplates, though this was significantly different in the XLIF group (65 vs 52 %, respectively). ALL damage was observed in 3 MAS TLIF levels. Percentage of endplate that was deemed to have complete disc removal was highest in XLIF group with 90 % compared to 65 % in MAS TLIF group, 43 % in MAS PLIF, and 40 % in mini-ALIF group. Endplate damage area was highest in the MAS TLIF group at 48 % and lowest in XLIF group at 4 %.
Conclusions
These results demonstrate that adequate endplate preparation for interbody fusion can be achieved utilizing various minimally invasive approach techniques (mini-ALIF, MAS TLIF, MAS PLIF, XLIF), however, XLIF appears to provide a greater area of and more complete endplate preparation.
Restoring sagittal alignment is an important factor in the treatment of spinal deformities. Recent investigations have determined that releasing the anterior longitudinal ligament (ALL) and placing hyperlordotic cages can increase lordosis, while minimizing need for 3 column osteotomies. The influences of parameters such as cage height and angle have not been determined. Finite element analysis was employed to assess the extent of lordosis achievable after placement of different sized lordotic cages.
Methods
A 3-dimensional model of a L3–4 segment was used. Disc distraction was simulated by inserting interbody cages mid-body in the disc space. Analyses were performed in the following conditions: (1) intact, (2) ALL release, (3) ALL release + facetectomy, and (4) ALL release + posterior column osteotomy. Changes in segmental lordosis, disc height, foraminal height, and foraminal area were measured.
Results
After ALL resection and insertion of hyperlordotic cages, lordosis was increased in all cases. The lordosis achieved by the shorter cages was less due to posterior disc height maintained by the facet joints. A facetectomy increased segmental lordosis, but led to contact between the spinous processes. For some configurations, a posterior column osteotomy was required if the end goal was to match cage angle to intradiscal angle.
Conclusion
Increased segmental lumbar lordosis is achievable with hyperlordotic cages after ALL resection. Increased cage height tended to increase the amount of lordosis achieved, although in some cases additional posterior bone resection was required to maximize lordosis. Further studies are needed to evaluate the impact on regional lumbar lordosis.
The aim of the study is to assess and quantify the effectiveness of interbody lordotic cages applied by trans-psoas approach to improve radiographic parameters, showing the differences between completely mini-invasive and hybrid approach.
Methods
We collected data of 65 patients affected by degenerative lumbar deformity/diseases and underwent mini-invasive lateral interbody fusion followed by percutaneous (group A, completely mini-invasive) or open (group B, hybrid) posterior instrumentation. A subgroup underwent anterior column realignment (ACR). We assessed statistical differences in preoperative and postoperative (at least 6-month) coronal and sagittal parameters, and disc angle (DA) at each level of cage application.
Results
107 lordotic cages were implanted. Group B had the most significant mean changes, especially in coronal Cobb angle, sagittal vertical axis, lumbar lordosis (LL), pelvic incidence-LL mismatch and DA. Concerning DA, at each level of lordotic cage application, in group A changed from ?2.9° preop to ?6.5° postop (p = 0.01); in group B, DA changed from ?2.6° to ?9.5° (p = 0.002) and from +1° to ?13.2° in patients underwent ACR.
Conclusions
Minimally invasive lateral lumbar interbody fusion is an effective technique in improving sagittal parameters. When combined with posterior open approach and/or application of ACR procedure greater corrections are possible.
To investigate whether axial loading of the spine during MRI (alMRI) instantaneously induces changes in biochemical disc features as reflected by altered quantitative T2 values in patients with chronic low back pain (LBP).
Methods
T2 mapping was performed on 11 LBP patients (54 lumbar discs) during the conventional unloaded MRI and subsequent alMRI. Each disc was divided into five volumetric regions of interests (ROIs), anterior annulus fibrosus (AF) (ROI 1), the interface anterior AF-nucleus pulposus (NP) (ROI 2), NP (ROI 3), the interface NP-posterior AF (ROI 4), and the posterior AF (ROI 5). The mean T2 values for each ROI were compared between MRI and alMRI and correlated with degeneration grade (Pfirrmann), disc angle, and disc level.
Results
With alMRI, T2 values increased significantly in the whole disc as well as in various parts of the disc with an increase in ROI 1–3 and a decrease in ROI 5. The changes in T2 values correlated to degeneration grade, changes in disc angle, and lumbar level.
Conclusion
alMRI instantaneously induces T2-value changes in lumbar discs and is, thus, a feasible method to reveal dynamic, biochemical disc features in patients with chronic LBP.
The aim of this study is to compare the clinical, radiological and functional outcome of anterior versus posterior surgical debridement and fixation in patients with thoracic and lumbar tuberculous spondylodiscitis.
Patients and methods
A total number of 42 patients with tuberculous spondylodiscitis of the thoracic and lumbar spine treated surgically were included in this study. Twenty patients (group A) underwent anterior debridement, decompression and instrumentation by anterior approach. Twenty-two patients (group B) were operated by posterolateral (extracavitary) decompression and posterior instrumentation. Operative parameters, clinical, radiographic and functional results for the two groups were analyzed and compared.
Results
The average follow-up period was 15 months (range 12–24) in both groups. The average operative time, blood loss and blood transfusion of anterior group were significantly less than the posterior one. There was significant better back pain relief, kyphotic angle correction and less angle loss in the posterior group than anterior. There was no significant difference between the two groups regarding neurological recovery, functional outcome and fusion rate.
Conclusion
Both anterolateral and posterolateral approaches are sufficient for achieving the goals of surgical treatment of thoracic and lumbar Pott’s disease but posterolateral approach allows significant better kyphotic angle correction, less angle loss, better improvement in back pain but unfortunately more operative time and blood loss.
To assess, with finite element analysis and an in vitro biomechanical study in cadaver, whether the implementation of an anterior interbody cage made of hedrocel with nitinol shape memory staples in compression increases the stiffness of the stand-alone interbody cage and to compare these constructs’ stiffness to other constructs common in clinical practice.
Methods
A biomechanical study with a finite element analysis and cadaveric testing assessed the stiffness of different fixation modes for the L4–L5 functional spinal unit: intact spine, destabilized spine with discectomy, posterior pedicle-screw fixation, anterior stand-alone interbody cage, anterior interbody cage with bilateral pedicle screws and anterior interbody cage with two shape memory staples in compression. These modalities of vertebral fixation were compared in four loading modes (flexion, extension, lateral bending, and axial rotation).
Results
The L4–L5 spinal unit with an anterior interbody cage and two staples was stiffer than the stand-alone cage. The construct stiffness was similar to that of a model of posterior pedicular stabilization. The stiffness was lower than that of the anterior cage plus bilateral pedicle-screw fixation.
Conclusion
The use of an anterior interbody implant with shape memory staples in compression may be an alternative to isolated posterior fixation and to anterior isolated implants, with increased stiffness.
Our aim was to study the safety and outcomes of posterior instrumentation and transforaminal lumbar interbody fusion (TLIF) for treating pyogenic lumbar spondylodiscitis.
Methods
Retrospective analysis was performed on prospectively collected data of 27 consecutive cases of lumbar pyogenic spondylodiscitis treated with posterior instrumentation and TLIF between January 2009 and December 2012. Cases were analysed for safety, radiological and clinical outcomes of transforaminal interbody fusion using bone graft?±?titanium cages. Interbody metallic cages with bone graft were used in 17 cases and ten cases used only bone graft. Indications for surgical treatment were failed conservative management in 17, neurodeficit in six and significant bony destruction in four.
Results
There were no cases reporting cage migration, loosening, pseudoarthrosis or recurrence of infection at a mean follow-up of 30 months. Clinical outcomes were assessed using Kirkaldy–Willis criteria, which showed 14 excellent, nine good, three fair and one poor result. Mean focal deformity improved with the use of bone graft?±?interbody cages, and the deformity correction was maintained at final follow-up. Mean pre-operative focal lordosis for the graft group was 8.5° (2–16.5°), which improved to 10.9 °(3.3–16°); mean pre-operative focal lordosis in the group treated with cages was 6.7 °(0–15°), which improved to 7°(0–15°) .
Conclusion
TLIFs with cages in patients with pyogenic lumbar spondylodiscitis allows for acceptable clearance of infection, satisfactory deformity correction with low incidence of cage migration, loosening and infection recurrence.
To determine the safety and short-term curative effects of internal fixation using a dynamic neutralization system (Dynesys) for multi-segmental lumbar disc herniation (ms-LDH) with the control group treated by posterior lumbar interbody fusion (PLIF).
Methods
Forty-five patients with ms-LDH were selected as study group treated with Dynesys and 40 patients as control group with PLIF. The surgical efficacy was evaluated by comparing the visual analogue scale (VAS) scores, the Oswestry Disability Index (ODI) scores and the ROMs of the adjacent segment before and after surgery. The postoperative complications related to the implants were identified.
Results
All patients were followed up for an average duration of over 30 months. Dynesys stabilization resulted in significantly higher preservation of motion at the index level (p < 0.001), and significantly less (p < 0.05) hypermobility at the adjacent segments. VAS for back and leg pain and ODI improved significantly (p < 0.05) with both the methods, but there was no significant difference between the groups.
Conclusions
The non-fusion fixation system Dynesys is safe and effective regarding short-term curative effects for the treatment of ms-LDH.
Pyogenic infections of the lumbar spine are a rare but critical pathology, yet with considerably high mortality rates. In cases indicating surgical therapy, the implantation of titanium cages or autologous bone grafts represent today's gold standard. Although non-metallic implants such as poly-ether-ether-ketone (PEEK) have proven to be advantageous in diverse degenerative conditions, their saftey and practicability in lumbar spine infection remains questionable. Moreover, the efficacy of a single-step radical debridement of the infected disc space with subsequent fusion from a strictly posterior approach continues to be an issue of debate. We therefore sought to evaluate the feasibility, clinical and radiological outcome of a single-step TLIF procedure using oblique PEEK cages in the surgical management of patients with lumbar pyogenic spondylodiscitis.
Methods
From January 2009 through December 2013, all patients meeting the indication for surgical treatment of lumbar pyogenic spondylodiscitis were included. Patients demonstrating intact cortical bone on preoperative CT received a single-step radical debridement of the infected intervertebral disc space, posterior screw-and-rod instrumentation and implantation of an oblique PEEK cage using the TLIF technique. Oral antibiotics were continued for 12 weeks postoperatively and clinical and radiological results recorded throughout a minimum 1-year clinical follow-up.
Results
A total of 104 patients were admitted to receive surgical therapy for lumbar pyogenic spondylodiscitis. Within this patient population, 18 patients met the diagnostic criteria to receive the implantation of an oblique PEEK cage. Pathogens were detected in 13 cases with Staph. aureus being the predominant causative organism. All patients were discharged to recover in their domestic environment. Throughout the first year of clinical and radiological follow-up and beyond, none of the 18 patients demonstrated any signs of residual neurologic deficits or recurrent infection. Furthermore, two-plane conventional X-rays showed no significant implant subsidence or failure at any of the given time-points in up to 5 years postoperatively.
Conclusions
In patients meeting the criteria for surgical treatment of lumbar pyogenic spondylodiscitis, the implantation of PEEK cages using a single-step TLIF approach is a safe and feasible procedure. Based on our experience, the concern of a recurrent infection when implanting non-metallic cages may be refuted in carefully selected patients.
To identify predictors of both intermediate and long-term unfavorable outcomes after first time, uncomplicated lumbar disc surgery.
Methods
Patients (n = 120) who had undergone lumbar disc surgery were followed up 1.5 and 12 years thereafter. Baseline assessments were carried out 5–8 days after surgery. Clinical outcome was assessed in both follow-ups using the Low Back Pain Rating Scale. Statistical analysis included binary logistic and linear regression.
Results
Unfavorable outcomes were found in 50.5 % (1.5 years) and 52.6 % (12 years) of patients available for follow-up examination. Low pre-operative physical activity and severe pain in the first week after surgery were predictive of an unfavorable post-operative outcome at both follow-ups.
Conclusions
Identified predictors suggest that particular emphasis should put on comprehensive post-operative care at large and encouragement to adapt a physically active lifestyle in particular in rehabilitation concepts after first time uncomplicated lumbar disc surgery.
Recently, strategies aimed at optimizing provider factors have been proposed, including regionalization of surgeries to higher volume centers and adoption of volume standards. With limited literature promoting the regionalization of spine surgeries, we undertook a systematic review to investigate the impact of surgeon volume on outcomes in patients undergoing spine surgery.
Methods
We performed a systematic review examining the association between surgeon volume and spine surgery outcomes. To be included in the review, the study population had to include patients undergoing a primary or revision spinal procedure. These included anterior cervical discectomy and fusion (ACDF), anterior/posterior cervical fusion, laminectomy/decompression, anterior/posterior lumbar decompression with fusion, discectomy, and spinal deformity surgery (spine arthrodesis).
Results
Studies were variable in defining surgeon volume thresholds. Higher surgeon volume was associated with a significantly lower risk of postoperative complications, a lower length of stay (LOS), lower cost of hospital stay and a lower risk of readmissions and reoperations/revisions.
Conclusions
Findings suggest a trend towards better outcomes for higher volume surgeons; however, further study needs to be carried out to define objective volume thresholds for individual spine surgeries for surgeons to use as a marker of proficiency.
To compare the clinical effectiveness of decompression plus fusion and decompression alone for patients with degenerative lumbar spondylolisthesis, a systematic review and meta-analysis of all available evidence was performed.
Methods
A search of the literature was conducted on PubMed/MEDLINE, EMBASE, and the Cochrane Collaboration Library. Relevant studies comparing decompression plus fusion and decompression alone were selected according to eligibility criteria. Predefined endpoints were extracted and meta-analyzed from the identified studies.
Results
Four randomized controlled trials and 13 observational studies were eligible. The pooled data revealed that fusion was associated with significantly higher rates of satisfaction and lower leg pain scores when compared with decompression alone. However, fusion significantly increased the intraoperative blood loss, operative time and hospital stay. Both techniques had similar ODI, back pain scores, complication rate, and reoperation rate.
Conclusions
Based on the available evidence, decompression plus fusion maybe be better than decompression alone in the treatment of degenerative spondylolisthesis. Fusion had advantages of improvement of clinical satisfaction, as well as reduction of postoperative leg pain, with similar complication rate to decompression alone.
Conventional lumbar arthrodesis for the treatment of degenerative spondylolisthesis (DS) is associated with high complication rates and variable clinical efficacy. Modern minimally invasive (MIS) approaches may reduce the morbidity and produce greater clinical improvement compared to traditional surgical techniques. The objective of this study is to report radiographic outcomes and evaluate clinical improvements in the context of substantial clinical benefit for DS patients treated with a MIS 90° lateral, transpsoas approach for lumbar interbody fusion.
Methods
From 2005 to 2011, 60 consecutive patients were treated with MIS lateral interbody fusion for Grade I or II DS at a single institution. Mean patient age was 68 years, 75 % were female, and 30 % had undergone previous lumbar surgery. A total of 71 levels were treated, supplemental posterior fixation was used in 57 (95 %) cases, and 26 (43 %) patients underwent additional direct posterior decompression.
Results
Average follow-up was 20.3 months. Average ORT, EBL, and LOS were 206 min, 83 cc, and 1.29 days, respectively. Complications occurred in 3 (5 %) patients. Transient approach-related thigh/groin pain was observed in 5 (8 %) cases. There were no cases of pseudoarthrosis. At 1 year, LBP improved 71 %, LP improved 68 %, ODI decreased 52 %, and SF-36 PCS and MCS improved 43 and 21 %, respectively. Substantial clinical benefit was met by 94.7 % of patients on NRS LBP, by 84.6 % on NRS LP, by 83.7 % on ODI, and by 66.7 % on SF-36 PCS. Disc height increased 71 % and segmental lordosis increased 27.8 % at treated levels. Foraminal height, width, and volume increased 19.7, 18.0, and 39.6 %, respectively. Slip improved 60.7 % with interbody fusion only and further improved to 69.2 % after the placement of supplemental instrumentation.
Conclusions
MIS lateral interbody fusion in the treatment of DS resulted in significant improvements in clinical and radiographic outcomes, with a low complication rate and a high proportion of patients achieving substantial clinical benefit.
