Limitations and complications of minimally invasive spinal surgery in adult deformity

Advances and Challenges in Minimally Invasive Spine Surgery

Minimally invasive spine surgery continues to grow and develop. Over the past 50 years, there has been immense growth within this subspecialty of neurosurgery. A deep understanding of the historical context and future directions of this subspecialty is imperative to developing safe adoption and targeted innovation. This review aims to describe the advancements, and challenges that we face today in minimally invasive spine surgery.

Early Experience with Prone Lateral Interbody Fusion in Deformity Correction: A Single-Institution Experience

Background/Objectives: Lateral spine surgery offers effective minimally invasive deformity correction, but traditional approaches often involve separate anterior, lateral, and posterior procedures. The prone lateral technique streamlines this process by allowing single-position access for lateral and posterior surgery, potentially benefiting from the lordosing effect of prone positioning. While previous studies have compared prone lateral to direct lateral for adult degenerative diseases, this retrospective review focuses on the outcomes of adult deformity patients undergoing prone lateral interbody fusion. Methods: Ten adult patients underwent single-position prone lateral surgery for spine deformity correction, with a mean follow-up of 18 months. Results: Results showed significant improvements: sagittal vertical axis decreased by 2.4 cm, lumbar lordosis increased by 9.1°, pelvic tilt improved by 3.3°, segmental lordosis across the fusion construct increased by 12.2°, and coronal Cobb angle improved by 6.3°. These benefits remained consistent over the follow-up period. Correlational analysis showed a positive association between improvements in PROs and SVA and SL. When compared to hybrid approaches, prone lateral yielded greater improvements in SVA. Conclusions: Prone lateral surgery demonstrated favorable outcomes with reasonable perioperative risks. However, further research comparing this technique with standard minimally invasive lateral approaches, hybrid, and open approaches is warranted for a comprehensive evaluation.

Advancing Prone-Transpsoas Spine Surgery: A Narrative Review and Evolution of Indications with Representative Cases

The Prone Transpsoas (PTP) approach to lumbar spine surgery, emerging as an evolution of lateral lumbar interbody fusion (LLIF), offers significant advantages over traditional methods. PTP has demonstrated increased lumbar lordosis gains compared to LLIF, owing to the natural increase in lordosis afforded by prone positioning. Additionally, the prone position offers anatomical advantages, with shifts in the psoas muscle and lumbar plexus, reducing the likelihood of postoperative femoral plexopathy and moving critical peritoneal contents away from the approach. Furthermore, operative efficiency is a notable benefit of PTP. By eliminating the need for intraoperative position changes, PTP reduces surgical time, which in turn decreases the risk of complications and operative costs. Finally, its versatility extends to various lumbar pathologies, including degeneration, adjacent segment disease, and deformities. The growing body of evidence indicates that PTP is at least as safe as traditional approaches, with a potentially better complication profile. In this narrative review, we review the historical evolution of lateral interbody fusion, culminating in the prone transpsoas approach. We also describe several adjuncts of PTP, including robotics and radiation-reduction methods. Finally, we illustrate the versatility of PTP and its uses, ranging from 'simple' degenerative cases to complex deformity surgeries.

Advances and Evolving Challenges in Spinal Deformity Surgery

BACKGROUND

Surgical intervention is a critical tool to address adult spinal deformity (ASD). Given the evolution of spinal surgical techniques, we sought to characterize developments in ASD correction and barriers impacting clinical outcomes.

METHODS

We conducted a literature review utilizing PubMed, Embase, Web of Science, and Google Scholar to examine advances in ASD surgical correction and ongoing challenges from patient and clinician perspectives. ASD procedures were examined across pre-, intra-, and post-operative phases.

RESULTS

Several factors influence the effectiveness of ASD correction. Standardized radiographic parameters and three-dimensional modeling have been used to guide operative planning. Complex minimally invasive procedures, targeted corrections, and staged procedures can tailor surgical approaches while minimizing operative time. Further, improvements in osteotomy technique, intraoperative navigation, and enhanced hardware have increased patient safety. However, challenges remain. Variability in patient selection and deformity undercorrection have resulted in heterogenous clinical responses. Surgical complications, including blood loss, infection, hardware failure, proximal junction kyphosis/failure, and pseudarthroses, pose barriers. Although minimally invasive approaches are being utilized more often, clinical validation is needed.

CONCLUSIONS

The growing prevalence of ASD requires surgical solutions that can lead to sustained symptom resolution. Leveraging computational and imaging advances will be necessary as we seek to provide comprehensive treatment plans for patients.

Risk factors of early complications after thoracic and lumbar spinal deformity surgery: a systematic review and meta-analysis

PURPOSE

To determine risk factors increasing susceptibility to early complications (intraoperative and postoperative within 6 weeks) associated with surgery to correct thoracic and lumbar spinal deformity.

METHODS

We systematically searched the PubMed and EMBASE databases for studies published between January 1990 and September 2021. Observational studies evaluating predictors of early complications of thoracic and lumbar spinal deformity surgery were included. Pooled odds ratio (OR) or standardized mean difference (SMD) with 95% confidence intervals (CI) was calculated via the random effects model.

RESULTS

Fifty-two studies representing 102,432 patients met the inclusion criteria. Statistically significant patient-related risk factors for early complications included neurological comorbidity (OR = 3.45, 95% CI 1.83-6.50), non-ambulatory status (OR = 3.37, 95% CI 1.96-5.77), kidney disease (OR = 2.80, 95% CI 1.80-4.36), American Society of Anesthesiologists score > 2 (OR = 2.23, 95% CI 1.76-2.84), previous spine surgery (OR = 1.98, 95% CI 1.41-2.77), pulmonary comorbidity (OR = 1.94, 95% CI 1.21-3.09), osteoporosis (OR = 1.60, 95% CI 1.17-2.20), cardiovascular diseases (OR = 1.46, 95% CI 1.20-1.78), hypertension (OR = 1.37, 95% CI 1.23-1.52), diabetes mellitus (OR = 1.84, 95% CI 1.30-2.60), preoperative Cobb angle (SMD = 0.43, 95% CI 0.29, 0.57), number of comorbidities (SMD = 0.41, 95% CI 0.12, 0.70), and preoperative lumbar lordotic angle (SMD = - 0.20, 95% CI - 0.35, - 0.06). Statistically significant procedure-related factors were fusion extending to the sacrum or pelvis (OR = 2.53, 95% CI 1.53-4.16), use of osteotomy (OR = 1.60, 95% CI 1.12-2.29), longer operation duration (SMD = 0.72, 95% CI 0.05, 1.40), estimated blood loss (SMD = 0.46, 95% CI 0.07, 0.85), and number of levels fused (SMD = 0.37, 95% CI 0.03, 0.70).

CONCLUSION

These data may contribute to development of a systematic approach aimed at improving quality-of-life and reducing complications in high-risk patients.

Challenges Hindering Widespread Adoption of Minimally Invasive Spinal Surgery

Minimally invasive spinal surgery (MISS) techniques offer several beneficial prospects and are being increasingly requested by patients. However, these techniques have not been uniformly adopted by spinal surgeons, and they remain controversial among some. Several barriers have prevented widespread adoption of MISS. These include concerns regarding high start-up costs, limited evidence base, and lack of surgeon training. In addition, the unique approaches involved in MISS expose spinal surgeons to unfamiliar anatomy. Further, while MISS can address a growing spectrum of spinal pathology, some conditions, as well as complications encountered during MISS procedures, require open surgery. This requires surgeons to not only acquire the new and specialized MISS skillset but also maintain their ability to perform open surgery. These factors present challenges common to developing and innovative surgical techniques. Here, we review the barriers preventing wider adoption of MISS and present a framework to promote the safe and effective growth of MISS.

Comparison of Patient Preference, Understanding, and Sentiment for Minimally Invasive Versus Open Spine Surgery

STUDY DESIGN

Retrospective questionnaire analysis.

OBJECTIVE

The goal of this study was to analyze patients' understanding and preferences for minimally invasive spine (MIS) versus open spine surgery.

SUMMARY OF BACKGROUND DATA

MIS surgery is increasing in prevalence. However, there is insufficient literature to evaluate how the availability of MIS surgery influences the patients' decision-making process and perceptions of spine procedures.

METHODS

A survey was administered to patients who received a microdiscectomy or transforaminal lumbar interbody fusion between 2016 and 2020. All eligible patients were stratified into two cohorts based on the use of minimally invasive techniques. Each cohort was administered a survey that evaluated patient preferences, perceptions, and understanding of their surgery.

RESULTS

One hundred fifty two patients completed surveys (MIS: 88, Open: 64). There was no difference in time from surgery to survey (MIS: 2.1 ± 1.4 yrs, Open: 1.9 ± 1.4 yrs; P = 0.36) or sex (MIS: 56.8% male, Open: 53.1% male; P = 0.65). The MIS group was younger (MIS: 53.0 ± 16.9 yrs, Open: 58.2 ± 14.6 yrs; P = 0.05). More MIS patients reported that their technique influenced their surgeon choice (MIS: 64.0%, Open: 37.5%; P  < 0.00001) and increased their preoperative confidence (MIS: 77.9%, Open: 38.1%; P  < 0.00001). There was a trend towards the MIS group being less informed about the intraoperative specifics of their technique (MIS: 35.2%, Open: 23.4%; P = 0.12). More of the MIS cohort reported perceived advantages to their surgical technique (MIS: 98.8%, Open: 69.4%; P < 0.00001) and less reported disadvantages (MIS: 12.9%, Open: 68.8%; P < 0.00001). 98.9% and 87.1% of the MIS and open surgery cohorts reported a preference for MIS surgery in the future.

CONCLUSION

Patients who received a MIS approach more frequently sought out their surgeons, were more confident in their procedure, and reported less perceived disadvantages following their surgery compared with the open surgery cohort. Both cohorts would prefer MIS surgery in the future. Overall, patients have positive perceptions of MIS surgery.Level of Evidence: 3.

Understanding the Future Prospects of Synergizing Minimally Invasive Transforaminal Lumbar Interbody Fusion Surgery with Ceramics and Regenerative Cellular Therapies

Transforaminal lumber interbody fusion (TLIF) is the last resort to address the lumber degenerative disorders such as spondylolisthesis, causing lower back pain. The current surgical intervention for these abnormalities includes open TLIF. However, in recent years, minimally invasive TLIF (MIS-TLIF) has gained a high momentum, as it could minimize the risk of infection, blood loss, and post-operative complications pertaining to fusion surgery. Further advancement in visualizing and guiding techniques along with grafting cage and materials are continuously improving the safety and efficacy of MIS-TLIF. These assistive techniques are also playing a crucial role to increase and improve the learning curve of surgeons. However, achieving an appropriate output through TLIF still remains a challenge, which might be synergized through 3D-printing and tissue engineering-based regenerative therapy. Owing to their differentiation potential, biomaterials such as stem/progenitor cells may contribute to restructuring lost or damaged tissues during MIS-TLIF, and this therapeutic efficacy could be further supplemented by platelet-derived biomaterials, leading to improved clinical outcomes. Thus, based on the above-mentioned strategies, we have comprehensively summarized recent developments in MIS-TLIF and its possible combinatorial regenerative therapies for rapid and long-term relief.

Incidence and Risk Factors of Anterior Longitudinal Ligament Rupture After Posterior Corrective Surgery Using Lateral Lumbar Interbody Fusion for Adult Spinal Deformity

STUDY DESIGN

A retrospective single-center study.

OBJECTIVE

The objective of this study was to assess the incidence of anterior longitudinal ligament rupture (ALLR) and to identify the risk factors for ALLR in patients with adult spinal deformity (ASD).

SUMMARY OF BACKGROUND DATA

Lateral lumbar interbody fusion (LIF) has been widely used for ASD surgery. However, ALLR has been occasionally identified after posterior spinal correction surgery.

MATERIALS AND METHODS

The study included 43 consecutive patients (8 male and 35 female patients) who underwent posterior corrective surgery involving LIF (128 levels) for ASD between 2014 and 2018. The mean age was 72±7 years (range: 62-81 y), and the minimum follow-up period was 1 year [mean: 34±15 mo (range: 12-58 mo)]. Posterior correction and fusion surgery using the cantilever technique was performed following LIF. Oblique LIF was performed in 27 patients, and extreme lateral interbody fusion (XLIF) was performed in 16 patients. The mean number of spinal fused levels was 8.9±1.8 levels (range: 8-15), and the mean number of LIF levels was 3±0.6 levels (range: 2-4). ALLR was considered if a LIF cage showed no contact with the vertebral endplates. The radiographic parameters were thoracic kyphosis, lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt, and sagittal vertical axis.

RESULTS

ALLR occurred in 10 patients (22%) and at 11 levels (8.6%). XLIF and preexisting osteoporotic vertebral fracture were identified as independent risk factors for ALLR. The change in LL was ∼10 degrees greater in the ALLR group than in the non-ALLR group (P=0.017), and overcorrection was observed in the ALLR group (PI-LL: -7.9±7 degrees). The change in the segmental lordotic angle at the ALLR level was much larger than after LIF and correction surgery. ALLR-related reoperation was performed in 2 cases (decompression surgery owing to posterior impingement and rod breakage).

CONCLUSIONS

ALLR occurred in 10 patients (22%). XLIF and preexisting osteoporotic vertebral fracture were independent risk factors for ALLR. Overcorrection was observed in patients with ALLR.

Revision Surgery Rates After Minimally Invasive Adult Spinal Deformity Surgery: Correlation with Roussouly Spine Type at 2-Year Follow-Up?

BACKGROUND

Spinopelvic parameters have hitherto dictated much of adult spinal deformity (ASD) correction. The Roussouly classification is used for the normal adult spine. We evaluated whether a correlation would be found between the Roussouly type and the rate of revision surgery in patients with ASD undergoing circumferential minimally invasive spinal (cMIS) correction.

METHODS

A multicenter retrospective review of patients who had undergone cMIS surgery for ASD was performed. The inclusion criteria were age ≥18 years and 1 of the following: coronal Cobb angle >20°, sagittal vertical axis >5 cm, pelvic tilt >20°, pelvic incidence (PI) to lumbar lordosis (LL) mismatch >10°, cMIS surgery, and a minimum of 2 years of follow-up data available. The patients were classified by Roussouly type, and the clinical and radiographic outcomes were evaluated.

RESULTS

A total of 104 patients were included in the present analysis. Of the 104 patients, 41 had Roussouly type 1, 32 had type 2, 23 had type 3, and 8 had type 4. Preoperatively, the patients with type 4 had the highest PI (P = 0.002) and LL (P < 0.001). Postoperatively, the PI-LL mismatch, Cobb angle, and sagittal vertical axis were not different among the 4 groups. However, the patients with type 2 had had the highest rate of complications (type 1, 29.3%; type 2, 61.3%; type 3, 34.8%; type 4, 25.0%; P = 0.031). The reoperation rates were comparable (type 1, 19.5%; type 2, 38.7%; type 3, 13.0%; type 4, 12.5%; P = 0.097). The reoperation rates for adjacent segment degeneration or proximal junctional kyphosis were also comparable (P = 0.204 and P = 0.060, respectively).

CONCLUSIONS

We did not find a clear correlation between Roussouly type and the rate of revision surgery for adjacent segment disease or proximal junctional kyphosis in patients who had undergone cMIS surgery for ASD.

Analysis of the Functional and Radiological Outcomes of Lumbar Decompression without Fusion in Patients with Degenerative Lumbar Scoliosis

STUDY DESIGN

Retrospective study.

PURPOSE

This study aimed to analyze the functional and radiological outcomes of lumbar decompression in patients with degenerative lumbar scoliosis (DLS).

OVERVIEW OF LITERATURE

Patients with DLS have symptoms related to lumbar canal stenosis (LCS) and those due to compensated spinal imbalance. Whether the deformity is the cause of pain or is an adaptive change for the ongoing LCS remains debatable. The extensive surgery for deformity correction along with spinal fusion is reported to have high perioperative morbidity and complication rate.

METHODS

This retrospective analysis involved 51 patients who underwent lumbar decompression for LCS associated with DLS from October 2006 to October 2016. The magnitude of the curve was determined using Cobb's angle and lumbar lordosis (D12-S1) on the preoperative and final follow-up, respectively. The Visual Analog Scale (VAS) and modified Oswestry Disability Index (mODI) scores at the preoperative and final follow-up indicated the functional outcome. Statistical analyses were performed using Student t -test.

RESULTS

All 51 patients were included in the statistical analyses. The mean patient age at presentation was 63.88±7.21 years. The average follow-up duration was 48±18.10 months. The average change in the Cobb's angle at the final follow-up was statistically insignificant (1°±1.5°, p=0.924; 20.8°±5.1° vs. 21.9°±5.72°). The mean change in lumbar lordosis at the final follow-up was statistically insignificant (3.29°±1.56°, p=0.328; 30.2°±7.9° vs. 27.5°±7.1°). There was statistically insignificant worsening in the back VAS scores at the final follow-up (4.9±1.9 vs. 6.0±1.2, p=0.07). There was statistically significant improvement in the leg pain component of the VAS score at the final follow-up (5.8±1.05 vs. 2.6±1.2, p<0.001). There was statistically significant improvement in the mODI scores at the final follow-up (p<0.001).

CONCLUSIONS

Lumbar decompression in DLS is associated with good functional outcome, especially when the symptoms are related to LCS. Curve progression following lumbar decompression is very less at mid-term and is similar to that in the natural course of the disease.

Complication avoidance in minimally invasive spinal surgery

Minimally invasive techniques in spinal surgery allow surgeons to perform operations with less of the approach-related morbidity inherent to traditional open procedures. Yet these muscle-sparing procedures come with a unique set of risks that stem from the novel approaches, limited exposure, and/or a restricted working corridor that they employ. The literature suggests that these operations can be performed without an increased rate of complication once the associated learning curve has been surmounted, suggesting that knowledge of and experience with the nuances of these procedures are essential for patient safety. The present article describes the complications specific to a variety of minimally invasive spinal surgeries and provides guidance on how to avoid them.

Using minimally invasive techniques adds to the value equation for select patients

Conditions of the spine are one of the most prevalent causes of global disability, and result in a considerable portion of total health expenditures. Surgical treatment of the spine has been demonstrated in multiple studies to be a cost-effective treatment option for many patients, especially with continuing improvements in surgical technique and instrumentation. Minimally invasive spine surgery (MISS), in particular, has evolved as a valuable option in treating certain patients. Numerous studies have analyzed minimally invasive techniques in regards to cost-effectiveness and other purported advantages. These advantages include conduciveness to outpatient settings, better perioperative and immediate post-operative benefits, and faster time to recovery. This article will describe the current literature on the advantages of MISS, specifically in regards to value and cost savings.

Treatment of adult thoracolumbar spinal deformity: past, present, and future

Care of the patient with adult spinal deformity (ASD) has evolved from being primarily supportive to now having the ability to directly treat and correct the spinal pathology. The focus of this narrative literature review is to briefly summarize the history of ASD treatment, discuss the current state of the art of ASD care with focus on surgical treatment and current challenges, and conclude with a discussion of potential developments related to ASD surgery.In the past, care for ASD was primarily based on supportive measures, including braces and assistive devices, with few options for surgical treatments that were often deemed high risk and reserved for rare situations. Advances in anesthetic and critical care, surgical techniques, and instrumentation now enable almost routine surgery for many patients with ASD. Despite the advances, there are many remaining challenges currently impacting the care of ASD patients, including increasing numbers of elderly patients with greater comorbidities, high complication and reoperation rates, and high procedure cost without clearly demonstrated cost-effectiveness based on standard criteria. In addition, there remains considerable variability across multiple aspects of ASD surgery. For example, there is currently very limited ability to provide preoperative individualized counseling regarding optimal treatment approaches (e.g., operative vs nonoperative), complication risks with surgery, durability of surgery, and likelihood of achieving individualized patient goals and satisfaction. Despite the challenges associated with the current state-of-the-art ASD treatment, surgery continues to be a primary option, as multiple reports have demonstrated the potential for surgery to significantly improve pain and disability. The future of ASD care will likely include techniques and technologies to markedly reduce complication rates, including greater use of navigation and robotics, and a shift toward individualized medicine that enables improved counseling, preoperative planning, procedure safety, and patient satisfaction.Advances in the care of ASD patients have been remarkable over the past few decades. The current state of the art enables almost routine surgical treatment for many types of ASD that have the potential to significantly improve pain and disability. However, significant challenges remain, including high complication rates, lack of demonstrated cost-effectiveness, and limited ability to meaningfully counsel patients preoperatively on an individual basis. The future of ASD surgery will require continued improvement of predictability, safety, and sustainability.