Brian Fiani, a neurosurgeon at Weill Cornell Medicine/NewYork-Presbyterian Hospital (New York, USA), examines some of the main benefits and also limitations associated with minimally invasive surgery (MIS) for patients who suffer from spinal deformity, as well as what the future might hold for such techniques within the field.
MIS approaches for adult spinal deformity (ASD) have been increasingly popular in the past few years and will continue to grow. The large interest stems from the ability to decrease the complication rate profile and improve the patient recovery process. The limitation is the restricted extent of deformity correction.
While minimising complication rates, MIS techniques allow patients to have quicker recoveries, decreased hospitalisation length of days (lower cost), decreased intraoperative blood loss, and quicker return to daily activity. Not to mention, decreased radiation exposure to surgeon and patient is alluring.
The question remains as to what extent can the ADS be corrected through MIS approaches. Emerging techniques for MIS have allowed spine surgeons to perform anterior column realignment and posterior column osteotomies which are fundamental to deformity correction.
MIS approaches have proven to be less morbid, one way, is by minimising dissection. One can work through small tubular approaches, endoscopic approaches, or small self-retaining retractors to create a small working corridor.
The fact that one can still restore sagittal and coronal balance and construct multi-level fusions is quite promising, but not without scrutiny. Literature to date investigates spinal parameters in order to validate whether meaningful alignment corrections can be achieved. Patients are also investigated with disability index scores and pain scale surveys.
Spinal News International recently ran a poll asking physicians whether or not minimally invasive surgery has a role in treating those with spinal deformity. The results were as follows:
Advances in customised spinal instrumentation technology has allowed for multi-dimensional alignment changes to best suit the patient’s needs to restore balance. Expandable cages, along with navigation for placement, have popularized MIS for ASD.
Anterior column realignment is a process of releasing the anterior longitudinal ligament for maximising lordosis with a hyperlordotic cage and is a supplemental MIS technique for ASD correction.
‘Mini-open’ or hybrid approaches have been practiced by placing pedicle screws percutaneously and doing a planned osteotomy through ‘mini open’ midline subperiosteal dissection only at the osteotomy level which is used as a cantilever technique. Limitations certainly exist and patient selection is of much importance.
Long-term follow-up reports identify patient cohorts that have malalignment upon radiographic follow-up. Further, correlations exist that postoperative malalignment translates to worse clinical outcomes. It is theorised that proximal junction kyphosis after sagittal deformity correction is mitigated with MIS technique via preservation of posterior ligamentous structures.
In conclusion, tailored MIS techniques for ASD correction can be useful in a spine surgeon’s armamentarium, but patient selection and surgeon comfortability are important. As artificial intelligence and machine learning gains more traction, patient selection algorithms will guide the future direction of MIS for ASD.
Brian Fiani is an Ivy League fellowship trained neurosurgeon with subspecialty focus on spine surgery. He has authored over 120 peer-reviewed journal publications and two textbooks, and is the invited speaker at many regional and national conferences. Fiani is known as one of New York City’s top doctors.