Faculty Bibliography

Background/UNASSIGNED:Extreme lateral interbody fusions (XLIF) and Minimally Invasive (MIS) XLIF were developed to limit the vascular injuries associated with anterior lumbar interbody fusion (ALIF), and minimize the muscular/ soft tissue trauma attributed to transforaminal lumbar interbody fusion (TLIF), posterior lumbar interbody fusion (PLIF), and posterolateral lumbar fusion (PLF). Methods/UNASSIGNED:Nevertheless, XLIF/MIS XLIF pose significant additional risks and complications that include; multiple nerve injuries (e.g. lumbar plexus, ilioinguinal, iliohypogastric, genitofemoral, lateral femoral cutaneous, and subcostals (to the anterior abdominal muscles: abdominal oblique), and sympathectomy), major vascular injuries, bowel perforations/postoperative ileus, seromas, pseudarthrosis, subsidence, and reoperations. Results/UNASSIGNED:The risks of neural injury with XLIF/MIS XLIF (up to 30-40%) are substantially higher than for TLIF, PLIF, PLF, and ALIF. These neural injuries included: lumbar plexus injuries (13.28%); new sensory deficits (0-75% (21.7%-40%); permanent 62.5%); motor deficits (0.7-33.6%-40%); iliopsoas weakness (9%-31%: permanent 5%), anterior thigh/groin pain (12.5-34%), and sympathectomy (4%-12%). Additional non-neurological complications included; subsidence (10.3%-13.8%), major vascular injuries (0.4%), bowel perforations, recurrent seroma, malpositioning of the XLIF cages, a 45% risk of cage-overhang, pseudarthrosis (7.5%), and failure to adequately decompress stenosis. In one study, reviewing 20 publications and involving 1080 XLIF patients, the authors observed "Most (XLIF) studies are limited by study design, sample size, and potential conflicts of interest." Conclusion/UNASSIGNED:Many new neurological deficits and other adverse events/complications are attributed to MIS XLIF/ XLIF. Shouldn't these significant risk factors be carefully taken into consideration before choosing to perform MIS XLIF/XLIF?

Background/UNASSIGNED:Extreme lateral interbody fusions (XLIF) and Minimally Invasive (MIS) XLIF pose significant risks of neural injury to the; lumbar plexus, ilioinguinal, iliohypogastric, genitofemoral, lateral femoral cutaneous, and subcostal nerves. To limit these injuries, many intraoperative neural monitoring (IONM) modalities have been proposed. Methods/UNASSIGNED:Multiple studies document various frequencies of neural injuries occurring during MIS XLIF/XLIF: plexus injuries (13.28%); sensory deficits (0-75%; permanent 62.5%); motor deficits (0.7-33.6%; most typically iliopsoas weakness (14.3%-31%)), and anterior thigh/groin pain (12.5-25%.-34%). To avoid/limit these injuries, multiple IONM techniques have been proposed. These include; using finger electrodes during operative dissection, employing motor evoked potentials (MEP), eliminating (no) muscle relaxants (NMR), and using "triggered" EMGs. Results/UNASSIGNED:In one study, finger electrodes for XLIF at L4-L5 level for degenerative spondylolisthesis reduced transient postoperative neurological symptoms from 7 [38%] of 18 cases (e.g. without IONM) to 5 [14%] of 36 cases (with IONM). Two series showed that motor evoked potential monitoring (MEP) for XLIF reduced postoperative motor deficits; they, therefore, recommended their routine use for XLIF. Another study demonstrated that eliminating muscle relaxants during XLIF markedly reduced postoperative neurological deficits/thigh pain by allowing for better continuous EMG monitoring (e.g. NMR no muscle relaxants). Finally, a "triggered" EMG study" reduced postoperative motor neuropraxia, largely by limiting retraction time. Conclusion/UNASSIGNED:Multiple studies have offered different IONM techniques to avert neurological injuries following MIS XLIF/XLIF. Does this mean that these procedures (e.g. XLIF/MIS XLIF) are unsafe?

Background/UNASSIGNED:We as spine surgeons increasingly need to carefully screen our own patients for major medical/cardiac comorbidities to determine if they are candidates for spine surgery. Our medical/cardiac colleagues rarely understand how long anti-platelet aggregates and non-steroidal anti-inflammatories (NSAIDs) have to be stopped prior to spine operaeitons, and when it is safe for them to be reinstated. Case Study/UNASSIGNED:A patient over 65 years of age, presented with 6 months of increased bilateral lower extremity sciatica, and 2-block neurogenic claudication. The MR scan showed moderate to severe lumbar stenosis L2-S1 with grade I L4-L5 spondylolisthesis, and multiple bilateral synovial cysts. Nevertheless, his neurological examination was normal. Further, he had > 5 stents placed within the last five years, and had undergone cardiac surgery two years ago requiring placement of a bovine aortic valve, and resection of a left ventricular wall aneurysm. He was also still on full dose Aspirin (325 mg/day), and Clopidogrel (75 mg po bid). Notably, 3 prior spinal surgeons (neurosurgery/orthopedics) had recommended multilevel lumbar laminectomy with instrumented fusions (e.g. including multilevel transforaminal lumbar interbody fusions (TLIF)). Conclusions/UNASSIGNED:Despite multilevel L2-S1 stenosis, Grade I L4-L5 spondylolisthesis, and multilevel bilateral synovial cysts, the patient's normal neurological examination and multiple cardiac comorbidities (i.e. requiring continued full-dose ASA/Clopidogrel) precluded, in my opinion, offering surgical intervention. Rather, I referred the patient to neurology for conservative management. What would you have done?

Background/UNASSIGNED:Although the majority of patients with traumatic/atraumatic osteoporotic vertebral compression fractures (OVCFs) may be managed with non-surgical treatment (NST), a subset (e.g. 40%) with significant pain, loss of vertebral height, and other factors may warrant percutaneous vertebroplasty (V), or percutaneous kyphoplasty (K). Methods/UNASSIGNED:We compared the impact of these three treatment modalities, V, K, or NST, for managing OVCFs. Results/UNASSIGNED:In several studies, both V and K resulted in comparable improvement in pain relief, postoperative kyphotic angles, increased anterior vertebral heights, and frequency of leakage of bone cement. One study evaluating 16 RCT's (Randomized Controlled Studies), however, observed K significantly; "decreased the kyphotic wedge angle, increased the postoperative vertebral body height, and decreased the risk of cement leakage vs. V". Further, in some series, both V and K resulted in higher quality of life scores and better pain relief vs. NST, while other studies showed V was superior to K. Further, although the risk of adjacent level fractures (ALF) following V, K, and NST were comparable in most studies, one clearly demonstrated NST had the lowest incidence of ALF. Despite all these findings, most studies concluded outcomes were comparable for all 3 groups. Conclusions/UNASSIGNED:Although most OVCFs are still managed with non-surgical treatment (NST), a subset (e.g. about 40%) may warrant V or K. Although both V and K have been shown to result in significantly better pain relief, higher quality of life scores, increased postoperative vertebral body height compared with NST, outcomes for all 3 groups remained the same.

Background/UNASSIGNED:MR/CT documented smaller cranial meningiomas in asymptomatic patients are often followed for years without requiring any intervention. Only a subset of patients who become symptomatic attributed to significant tumor growth, edema and/or mass effect may require stereotactic radiosurgery (SRS), and rarely, open surgery. Clearly, the decision for choosing any treatment modality must be made on a case by case basis and include an analysis of risks vs. benefits to the individual patient. Methods/UNASSIGNED:Patients with smaller benign asymptomatic meningiomas are followed with sequential MR studies that typically document lack of tumor progression, edema, or mass effect. Those who become symptomatic with the typical triad (i.e. headaches, seizures, or visual loss) and other focal neurological deficits may warrant SRS, and only occasionally, open surgery. Surgery may indeed be warranted in the presence of certain mitigating factors, (e.g. young age, lesions located adjacent to by not yet invading critical structures etc.). Results/UNASSIGNED:This review focused largely on smaller benign asymptomatic meningiomas. The non-operative/ conservative management vs. use of SRS vs. open surgery in select cases are discussed, along with a review of the morbidity/mortality of the respective interventions. Conclusion/UNASSIGNED:There are multiple treatment options for patients with smaller asymptomatic cranial meningiomas. SRS may be warranted for those who exhibit tumor growth, increasing edema, and/or mass effect. Only rarely is open operative intervention necessary; this must include consideration of other factors that may warrant early surgery. Notably, the 5-year survival rates for SRS ranged from 95.2% - 97%, while the 10-year survival rates varied from 88.6% - 94%.