What Are the Roles of Anterior, Lateral, and Antepsoas Interbody Approaches in Spinal Deformity Surgery?

The advantages of anterior, muscle-sparing interbody fusion for the management of degenerative scoliosis have been well defined in the literature. These include both direct and indirect decompression, restoration of disk/foraminal height and spinal biomechanics, correction of sagittal balance, and improved fusion rates. The continued evolution of minimally invasive techniques and surgical instrumentation has led to reduced morbidity for patients and increased popularity for anterior interbody techniques among surgeons. It is important to remember that when deciding on what interbody approach to use, the surgeon must consider goals of care, anatomic characteristics as seen on preoperative imaging, and surgical levels. Although each approach has distinct advantages and disadvantages, ultimately the most important deciding factor should lie with the surgeons' experience and comfort levels with each approach.

Surgery of the amygdala and uncus: a case series of glioneuronal tumors.

BACKGROUND: Patients with a lesion within the amygdala and uncus may develop temporal lobe epilepsy despite having functional mesial structures. Resection of functional hippocampus and surrounding structures may lead to unacceptable iatrogenic deficits. To our knowledge, there is limited descriptions of surgical techniques for selectively resecting the amygdala and uncus lesions while preserving the hippocampus in patients with language-dominant temporal lobe pathology. METHODS: Thirteen patients with language-dominant temporal lobe epilepsy related to amygdala-centric lesions were identified. Patients with sclerosis of the mesial structures or evidence of pathology outside of the amygdala-uncus region were excluded. Neuropsychological evaluation confirmed normal function of the mesial structures ipsilateral to the lesion. All patients were worked up with video-EEG, high-resolution brain MRI, neuro-psychology evaluation, and either Wada or functional MRI testing. RESULTS: All patients underwent selective resection of the lesion including amygdala and uncus with preservation of the hippocampus via a transcortical inferior temporal gyrus approach to the mesial temporal lobe. Pathology was compatible with glioneuronal tumors. Post-operative MRI demonstrated complete resection in all patients. Eight of the thirteen patients underwent post-operative neuropsychology evaluations and did not demonstrate any significant decline in tasks of delayed verbal recall or visual memory based on the Rey Auditory Verbal Learning Test (RAVLT). One patient showed a slight decrease in confrontation naming using the Boston Naming Test (BNT). Seizure freedom (Engel class I) was achieved in 12 of 13 patients. CONCLUSION: Selective transcortical amygdala and uncus resection with hippocampus preservation may be a reasonable way to achieve seizure control while sparing functional mesial structures.

Femoral nerve and lumbar plexus injury after minimally invasive lateral retroperitoneal transpsoas approach: electrodiagnostic prognostic indicators and a roadmap to recovery.

Injury to the lumbosacral (LS) plexus is a well-described complication after lateral retroperitoneal transpsoas approaches to the spine. The prognosis for functional recovery after lumbosacral plexopathy or femoral/obturator neuropathy is unclear. We designed a retrospective case-control study with patients undergoing one-level lateral retroperitoneal transpsoas lumbar interbody fusion (LLIF) between January 2011 and June 2016 to correlate electrodiagnostic assessments (EDX) to physiologic concepts of nerve injury and reinnervation, and attempt to build a timeline for patient evaluation and recovery. Cases with post-operative obturator or femoral neuropathy were identified. Post-operative MRI, nerve conduction studies (NCS), electromyography (EMG), and physical examinations were performed at intervals to assess clinical and electrophysiologic recovery of function. Two hundred thirty patients underwent LLIF. Six patients (2.6%) suffered severe femoral or femoral/obturator neuropathy. Five patients (2.2%) had immediate post-operative weakness. One of the six patients developed delayed weakness due to a retroperitoneal hematoma. Five out of six patients (83%) demonstrated EDX findings at 6 weeks consistent with axonotmesis. All patients improved to at least MRC 4/5 within 12 months of injury. In conclusion, neurapraxia is the most common LS plexus injury, and complete recovery is expected after 3 months. Most severe nerve injuries are a combination of neurapraxia and variable degrees of axonotmesis. EDX performed at 6 weeks and 3, 6, and 9 months provides prognostic information for recovery. In severe injuries of proximal femoral and obturator nerves, observation of proximal to distal progression of small-amplitude, short-duration (SASD) motor unit potentials may be the most significant prognostic indicator.

An analysis of quality of life (QOL) in patients with epilepsy and comorbid psychogenic nonepileptic seizures (PNES) after vagus nerve stimulation (VNS).

PURPOSE: Patients with epilepsy (PWE) may suffer from comorbid psychogenic nonepileptic seizures (PNES). The efficacy of vagus nerve stimulation (VNS) in the treatment of epilepsy and depression is established, however the impact on PNES is unknown. Since many patients with PNES have comorbid depression, we explored the impact on quality of life (QOL) that VNS has on PWE and PNES. METHODS: The video electroencephalogram (vEEG) of all patients who underwent VNS at our institution was reviewed. Patients diagnosed with both psychogenic seizures and epileptic seizures on their vEEG were included in this study. These patients were contacted, and given a QOLIE-31 survey to assess their quality of life after VNS. Patients also completed a separate survey created by our group to categorize the quartile of their improvement. Pre-operative psychiatric disease was retrospectively reviewed. RESULTS: From a period of 2001 to 2016, 518 patients underwent placement of VNS for drug resistant epilepsy (DRE) at our institution. In total, 16 patients were diagnosed with both epilepsy and PNES. 11/16 patients responded to our questionnaire and survey. 9 out of 11 patients felt that their epileptic seizures had improved after VNS, while 7 of the 11 patients felt that their psychogenic episodes had improved. 2(28.6%), 1 (14.3%), and 4 (57.1%) of participants said their PNES improved by 25-50%, 50-75%, and 75-100%, respectively. 3(27.3%), 3 (27.3%), 1 (9.1%), and 4 (36.4%) of the participants said their epileptic seizures improved by 0-25%, 25-50%, 50-75%, and 75-100%, respectively. The average overall score for quality of life for the study participants was found to be 51 (±8) out of 100. CONCLUSION: Patients with epilepsy and comorbid PNES may benefit from VNS. It is unclear whether the benefit is conferred strictly from decreased epileptic seizure burden. The possible effect on PNES may be related to the known effect of VNS on depression. Further studies are necessary to elucidate the role of VNS in the treatment of PNES and possibly other psychiatric disease.

Insertion of magnetically controlled growing rods in a patient with a diaphragmatic pacemaker: case report.

Phrenic stimulators offer an alternative to standard mechanical ventilation as well as the potential for ventilator independence in select patients with chronic respiratory failure. Young patients (< 10 years old) with high cervical spinal cord injuries often develop paralytic scoliosis due to loss of muscle tone caudal to their spinal cord lesion. Growing rod systems allow for stabilization of spinal deformity while permitting continued growth of the spine and thoracic cavity. Magnetically controlled growing rods (MCGRs) offer the advantage of noninvasive expansion, as opposed to the operative expansion required in traditional growing rod systems. To the authors' knowledge, this is the first reported case of MCGRs in a patient with a diaphragmatic pacemaker (DP). A 7-year-old boy with ventilator dependence after a high cervical spinal cord injury presented to the authors' institution with paralytic scoliosis that progressed to > 120°. The patient had previously undergone insertion of phrenic nerve stimulators for diaphragmatic pacing. The decision was made to insert MCGRs bilaterally to stabilize his deformity, because the planned lengthening surgeries that are necessary with traditional growing rods would be poorly tolerated in this patient. The patient's surgery and postoperative course were uneventful. The DP remained functional after insertion and lengthening of the MCGRs by using the external magnet. The DP had no effect on the expansion capability of the MCGRs. In conclusion, the MCGRs appear to be compatible with the DP. Further studies are needed to validate the long-term safety and compatibility of these 2 devices.

Temporal lobe epilepsy and cavernous malformations: surgical strategies and long-term outcomes.

OBJECTIVE: Cerebral cavernous malformations (CCM) of the temporal lobe often present with seizures. Surgical resection of these lesions can offer durable seizure control. There is, however, no universally accepted methodology for assessing and surgically treating these patients. We propose an algorithm to maximize positive surgical outcomes (seizure control) while minimizing post-surgical neurological deficit. METHODS: A retrospective review of 34 patients who underwent epilepsy surgery for radiographically proven temporal lobe CCM was conducted. Patients underwent a relatively standard work-up for seizure localization. In patients with mesial temporal lobe epilepsy (MTLE), a complete resection of the epileptogenic zone was performed including amygdalo-hippocampectomy in addition to a lesionectomy if not contraindicated by pre-operative work-up. Patients with neocortical epilepsy underwent intraoperative electrocorticography (ECoG)-guided lesionectomy. RESULTS: Seizure-free rate for mesial and neocortical (anterior, lateral, and basal) location was 90 vs. 83 %, respectively. Complete resection of the lesion, irrespective of location, was statistically significant for seizure control (p = 0.018). There was no difference in seizure control based on disease duration or location (p > 0.05). Patients with mesial temporal CCM who presented with MTLE were presumed to also have mesial temporal sclerosis (MTS), or dual pathology. These patients underwent routine resection of the mesial structures. Interestingly, patients who had MTLE and basal (neocortical) lesions who underwent a mesial resection for suspected MTS were found not to have dual pathology. CONCLUSIONS: Patients with temporal lobe CCM should be offered resection for durable seizure control, prevention of secondary epileptogenic foci, and elimination of hemorrhage risk. The preoperative work-up should follow a team approach. Surgical intervention should include complete lesionectomy in all cases. Intra or extra-operative ECoG for neocortical lesions may be beneficial. Management of mesial temporal CCMs (archicortex) should consider resection of a well-defined epileptogenic zone (including mesial structures) due to high probability of pathologically proven MTS. The use of this treatment algorithm is useful for the education and treatment of these patients.

Optimal trajectory for the occipital condyle screw.

STUDY DESIGN: Retrospective analysis. OBJECTIVE: To understand what may constitute an optimal trajectory for an occipital condyle (OC) screw. SUMMARY OF BACKGROUND DATA: OC screws are an alternative to standard occipital plates as a cephalad fixation point in occipitocervical fusion. An optimal trajectory for placement of OC screws has not been described. METHODS: We conducted a computed tomography-based study of 340 human occipital condyls. All computed tomographies were negative for traumatic, degenerative, and neoplastic pathology. On the basis of the current literature, linear measurements of distances were made based on a constant entry point. Medial angulations of 10, 20, and 25 degrees relative to the sagittal midline were used. In addition, 10-, 5-degree cranial, 10- and 30-degree caudal angulations were studied to evaluate the incidence of hypoglossal canal and atlantooccipital joint compromise. RESULTS: Average distances were 17.1±2.8, 20.4±2.8, and 22.2±2.9 for 10, 20, and 25 degrees of medial angulation, respectively. Right-sided and left-sided measurements for each category were not significantly different. However, the difference in the measured distances between 10 versus 20 degrees, 10 versus 25 degrees, and 20 versus 25 degrees was all significantly different (P<0.01). Hypoglossal canal compromise incidence was 0% and 7.1% for 5- and 10-degree cranial angulation, respectively. Atlantooccipital joint compromise incidence was 21.8% and 99.1% for 10- and 30-degree caudal angulation, respectively. CONCLUSIONS: The condylar entry point should be medial to the condylar fossa, midcondylar, and ≥2 mm caudal to the skull base. An optimal trajectory for the OC screw should have a medial angulation of ≥20 degrees relative to the sagittal midline, trying to stay parallel to the skull base. Minor adjustments in angulation can be made, but any adjustment approaching 10 degrees cranial or caudal leads to an increased risk of hypoglossal canal cranially or atlantooccipital joint compromise caudally.

Functional Stimulation and Imaging to Predict Neuromodulation of Chronic Low Back Pain.

Back pain is one of the most common aversive sensations in human experience. Pain is not limited to the sensory transduction of tissue damage; rather, it encompasses a range of nervous system activities including lateral modulation, long-distance transmission, encoding, and decoding. Although spine surgery may address peripheral pain generators directly, aberrant signals along canonical aversive pathways and maladaptive influence of affective and cognitive states can result in persistent subjective pain refractory to classical surgical intervention. The clinical identification of who will benefit from surgery-and who will not-is increasingly grounded in neurophysiology.

Metastatic secondary gliosarcoma: patient series.

BACKGROUND: Gliosarcoma is a rare and highly malignant cancer of the central nervous system with the ability to metastasize. Secondary gliosarcoma, or the evolution of a spindle cell-predominant tumor after the diagnosis of a World Health Organization grade IV glioblastoma, has also been shown to metastasize. There is little information on metastatic secondary gliosarcoma. OBSERVATIONS: The authors present a series of 7 patients with previously diagnosed glioblastoma presenting with recurrent tumor and associated metastases with repeat tissue diagnosis consistent with gliosarcoma. The authors describe the clinical, imaging, and pathological characteristics in addition to carrying out a systematic review on metastases in secondary gliosarcoma. LESSONS: The present institutional series and the systematic review of the literature show that metastatic secondary gliosarcoma is a highly aggressive disease with a poor prognosis.

The health care burden of patients with epilepsy in the United States: an analysis of a nationwide database over 15 years.

OBJECT: The aim of this study was to analyze the national health care burden of patients diagnosed with epilepsy in the US and to analyze any changes in the length of stay, mean charges, in-hospital deaths (mortality), and disposition at discharge. METHODS: A retrospective review of the Nationwide Inpatient Sample (NIS) database for epilepsy admissions was completed for the years from 1993 to 2008. The NIS is maintained by the Agency for Healthcare Research and Quality and represents a 20% random stratified sample of all discharges from nonfederal hospitals within the U.S. Patients with epilepsy were identified using ICD-9 codes beginning with 345.XX. Approximately 1.1 million hospital admissions were identified over a span of 15 years. RESULTS: Over this 15-year period (between 1993 and 2008), the average hospital charge per admission for patients with epilepsy has increased significantly (p < 0.001) from $10,050 to $23,909, an increase of 137.9%. This is in spite of a 33% decrease in average length of stay from 5.9 days to 3.9 days. There has been a decrease in the percentage of in-hospital deaths by 57.9% and an increase in discharge to outside medical institutions. CONCLUSIONS: The total national charges associated with epilepsy in 2008 were in excess of $2.7 billion (U.S. dollars, normalized). During the studied period, the cost per day for patients rose from $1703.39 to $6130.51. In spite of this drastic increase in health care cost to the patient, medical and surgical treatment for epilepsy has not changed significantly, and epilepsy remains a major source of morbidity.

The effect of the retroperitoneal transpsoas minimally invasive lateral interbody fusion on segmental and regional lumbar lordosis.

BACKGROUND: The minimally invasive lateral interbody fusion (MIS LIF) in the lumbar spine can correct coronal Cobb angles, but the effect on sagittal plane correction is unclear. METHODS: A retrospective review of thirty-five patients with lumbar degenerative disease who underwent MIS LIF without supplemental posterior instrumentation was undertaken to study the radiographic effect on the restoration of segmental and regional lumbar lordosis using the Cobb angles on pre- and postoperative radiographs. Mean disc height changes were also measured. RESULTS: The mean follow-up period was 13.3 months. Fifty total levels were fused with a mean of 1.42 levels fused per patient. Mean segmental Cobb angle increased from 11.10° to 13.61° (P < 0.001) or 22.6%. L2-3 had the greatest proportional increase in segmental lordosis. Mean regional Cobb angle increased from 52.47° to 53.45° (P = 0.392). Mean disc height increased from 6.50 mm to 10.04 mm (P < 0.001) or 54.5%. CONCLUSIONS: The MIS LIF improves segmental lordosis and disc height in the lumbar spine but not regional lumbar lordosis. Anterior longitudinal ligament sectioning and/or the addition of a more lordotic implant may be necessary in cases where significant increases in regional lumbar lordosis are desired.

Metastatic esthesioneuroblastoma recurrence after 19 years of remission: A systematic review with case illustration.

PURPOSE: Esthesioneuroblastoma (ENB) is a rare malignant neoplasm of the olfactory epithelium with an estimated incidence of 0.4/million. It can directly extend along the cribriform plate in order to metastasize to the central nervous system. However, non-contiguous intracranial involvement without recurrence at the primary site is extremely uncommon. In this report, the authors review the literature and present a case of non-contiguous intracranial metastasis of ENB without recurrence at the primary site. To the best of our knowledge, this case presents the longest disease-free interval reported in the literature. METHODS: A systematic review of literature was conducted in accordance with the PRISMA guidelines. Additionally, the presentation, surgical management, and post-operative outcomes of an 82-year-old female with non-contiguous intracranial metastasis of ENB after 19 years of remission are described. RESULTS: A total of 137 deduplicated works were identified after the search. Of these, 6 papers satisfied our inclusion criteria for our systematic review. Average age at presentation was 50.8 years (range: 26-66) and 52.6% of patients were female. A majority of cases achieved gross-total resection and received adjuvant radiotherapy for initial treatment. The median interval to intracranial metastasis was 6 years from the time of primary tumor presentation. The median overall survival from ENB recurrence with non-contiguous intracranial metastasis was 11.5 months. CONCLUSIONS: ENB is a highly recurrent tumor and harbors the potential to involve the intracranial space even years after remission. Intracranial involvement entails poor overall survival. Lifetime radiographic follow-up should be considered in all patients with ENB.

Neurosurgical Management of Interspinous Device Complications: A Case Series.

Background: Best practice guidelines for treating lumbar stenosis include a multidisciplinary approach, ranging from conservative management with physical therapy, medication, and epidural steroid injections to surgical decompression with or without instrumentation. Marketed as an outpatient alternative to a traditional lumbar decompression, interspinous process devices (IPDs) have gained popularity as a minimally invasive stabilization procedure. IPDs have been embraced by non-surgical providers, including physiatrists and anesthesia interventional pain specialists. In the interest of patient safety, it is imperative to formally profile its safety and identify its role in the treatment paradigm for lumbar stenosis. Case Description: We carried out a retrospective review at our institution of neurosurgical consultations for patients with hardware complications following the interspinous device placement procedure. Eight cases within a 3-year period were identified, and patient characteristics and management are illustrated. The series describes the migration of hardware, spinous process fracture, and worsening post-procedural back pain. Conclusions: IPD placement carries procedural risk and requires a careful pre-operative evaluation of patient imaging and surgical candidacy. We recommend neurosurgical consultation and supervision for higher-risk IPD cases.

Flexion-extension standing radiographs underestimate instability in patients with single-level lumbar spondylolisthesis: comparing flexion-supine imaging may be more appropriate.

BACKGROUND: Generally, most spine surgeons agree that increased segmental motion viewed on flexion-extension radiographs is a reliable predictor of instability; however, these views can be limited in several ways and may underestimate the instability at a given lumbar segment. METHODS: Consecutively collected adult (≥18 years old) patients with symptomatic single-level lumbar spondylolisthesis were reviewed from a two-surgeon database from 2015 to 2019. Routine standing lumbar X-rays (neutral, flexion, extension) and supine lumbar MRI (sagittal T2-weighted imaging sequence) were performed. Patients were excluded if they had prior lumbar surgery, missing radiographic data, or if the time between X-rays and MRI was >6 months. RESULTS: All 39 patients with symptomatic, single-level lumbar spondylolisthesis were identified. The mean age was 57.3±16.7 years and 66% were female. There was good intra- and inter-rater reliability agreement between measured values on the presence of instability. The slip percentage (SP) difference was significantly highest in the flexion-supine (FS) (5.7 mm, 12.3%) and neutral standing-supine (NS) (4.3 mm, 8.7%) groups, both of which were significantly higher compared with the flexion-extension (FE) group (1.8 mm, 4.5%, P<0.001). Ventral instability based on SP >8% was observed more frequently in FS (79.5%) and NS (52.6%) groups compared with FE group (16.7%, P<0.001). No statistically significant correlation was found between SP and disc angle for all radiographic views. CONCLUSIONS: Comparing standing lateral and flexion X-rays with supine MRIs provides higher sensitivity to assess instability than standard flexion-extension radiographs. The FS and NS comparisons also show greater slip percentage differences at higher slip grades, but not at different lumbar levels. These changes are not dependent on age or gender.

Novel Titanium Cages for Minimally Invasive Lateral Lumbar Interbody Fusion: First Assessment of Subsidence.

INTRODUCTION: Implant subsidence is a potential complication of spinal interbody fusion and may negatively affect patients subjected to procedures relying on indirect decompression such as minimally invasive transpsoas lateral lumbar interbody fusion (LLIF). The porous architecture of a recently developed titanium intervertebral cage maximizes bone-to-implant contact and minimizes stress shielding in laboratory experiments; however, its subsidence rate in patients has not yet been evaluated. The goal of this current study was to evaluate implant subsidence in patients subjected to LLIF. METHODS: Our institutional review board-approved single-center experience included 29 patients who underwent 30 minimally invasive LLIF from July 2017 to September 2018 utilizing the novel 3D-printed porous titanium implants. Radiographs, obtained during routine postoperative follow-up visits, were reviewed for signs of implant subsidence, defined as any appreciable compromise of the vertebral endplates. RESULTS: Radiographic subsidence occurred in 2 cases (6.7%), involving 2 out of 59 porous titanium interbody cages (3.4%). Both cases of subsidence occurred in four-level stand-alone constructs. The patients remained asymptomatic and did not require surgical revision. Ten surgeries were stand-alone constructs, and 20 surgeries included supplemental posterior fixation. CONCLUSIONS: In our patient cohort, subsidence of the porous titanium intervertebral cage occurred in 6.7% of all cases and in 3.4% of all lumbar levels. This subsidence rate is lower compared to previously reported subsidence rates in patients subjected to LLIF using polyetheretherketone implants.

The Effect of ACDF or Arthroplasty on Cervicogenic Headaches: A Post Hoc Analysis of a Prospective, Multicenter Study With 10-Year Follow-up.

STUDY DESIGN: This was a post hoc analysis of a prospective FDA-IDE study. OBJECTIVE: The purpose of this study is to determine the effectiveness of a 2-level anterior cervical discectomy and fusion (ACDF) or cervical disk arthroplasty (CDA) at relieving headaches associated with cervical radiculopathy or myelopathy at 10 years postoperative. BACKGROUND: To our knowledge, there is no large, prospective study that has examined the efficacy of cervical spine surgery for relieving headaches associated with radiculopathy or myelopathy at 10 years postoperative. MATERIALS AND METHODS: This was a post hoc analysis of a prospective FDA-IDE study for the Prestige LP versus ACDF for radiculopathy or myelopathy due to 2 levels. Preoperatively and out to 10 years, their Neck Disability Index documented if they had headaches (0: no headaches; 1: infrequent slight; 2: infrequent moderate; 3: frequent moderate; 4: frequent severe; 5: nearly constant). RESULTS: Three hundred ninety-seven patients were randomized to CDA (209) or ACDF (188). Preoperatively 86% had headaches and 55.9% (52.2% of CDA, 60.1% of ACDFs) had frequent moderate, severe, or nearly constant headache (grades 3-5). By 6 weeks postoperative, 64.4% had headaches and only 12.5% had grades 3-5 headaches (9.3% of CDA and 16% of ACDFs). The benefit lasted to the 10-year follow-up such that 60.3% had any headaches and 16.8% had grades 3-5 headaches (10.9% CDA; 24.3% ACDF). CONCLUSIONS: These results suggest that 86% of patients with radiculopathy or myelopathy complain of headaches preoperatively, with 55.9% having frequent or constant, moderate to severe headaches (grades 3-5). By 6 weeks postoperative, only 12.5% had grades 3-5 headaches. At 10-year follow-up, 16.8% had grades 3-5 headaches. Both arthroplasty and ACDF are often effective at alleviating headaches associated with radiculopathy or myelopathy.

Early and late hospital readmissions after spine deformity surgery in children with cerebral palsy.

STUDY DESIGN: Retrospective review of a prospectively collected multicenter registry of pediatric patients with cerebral palsy (CP) and neuromuscular scoliosis (NMS) undergoing spinal fusion. OBJECTIVE: To define risk factors for unplanned readmission after elective spinal deformity surgery. Patients with CP and NMS have high rates of hospital readmission; however, risk factors for readmission are not well established. METHODS: Univariate and multivariate analyses were used to compare the demographics, operative and postoperative course, radiographic characteristics, and preoperative Caregiver Priorities and Child Health Index of Life with Disabilities (CPCHILD) questionnaires of patients who did not require readmission to those who required either early readmission (within 90 days of the index surgery) or late readmission (readmission after 90 days). RESULTS: Of the 218 patients identified, 19 (8.7%) required early readmission, while 16 (7.3%) required late readmission. Baseline characteristics were similar between the three cohorts. On univariate analysis, early readmission was associated with longer duration of surgery (p < 0.001) and larger magnitude of residual deformity (p = 0.003 and p = 0.029 for postoperative major and minor angles, respectively). The health score of the CPCHILD Questionnaire was lower in patients who required early readmission than in those who did not require readmission (p = 0.032). On multivariate analysis, oral feeding status was inversely related to early readmission (less likely to require readmission), while decreasing lumbar lordosis and increasing length of surgery were related to an increased likelihood of early readmission. CONCLUSIONS: In patients with CP and NMS, longer surgical time, larger residual major and minor Cobb angles, lumbar lordosis, feeding status, and overall health may be related to a greater likelihood for early hospital readmission after elective spinal fusion. No factors were identified that correlated with an increased need for late hospital readmission after elective spinal fusion in patients with CP. LEVEL OF EVIDENCE: IV.

Incisional Hernia After Minimally Invasive Lateral Retroperitoneal Surgery: Case Series and Review of the Literature.

BACKGROUND: Minimally invasive lateral retroperitoneal (lateral-MIS) approaches to the spine involve traversing the lateral abdominal wall musculature and fascia. Incisional hernia is an uncommon approach-related complication. OBJECTIVE: To review the incidence, treatment, and preventative measures of incisional hernia after lateral-MIS approaches. METHODS: This is a retrospective review of cases performed by a single surgeon from 2011 to 2016. All patients who underwent lateral-MIS approaches at this institution were included. Patients with a postoperative diagnosis of lateral hernia on physical exam and corroborating advanced imaging findings were included in this study. Cases of flank bulge due to peripheral nerve injury were excluded. RESULTS: Three-hundred three patients underwent lateral-MIS approaches to the spine. Three (1%) patients with incisional hernia were identified. Two patients presented with a clinically symptomatic incisional hernia, while 1 patient was diagnosed incidentally after a routine abdominal magnetic resonance imaging for an unrelated reason. No patients suffered bowel entrapment or strangulation. CONCLUSION: Incisional hernia after lateral-MIS approaches is rare. Patients with incisional hernias may be susceptible to bowel incarceration and ischemia, though the incidence of this is probably low. Meticulous closure of the fascia is critical to avoiding this complication.

Development of Proximal Junctional Kyphosis After Minimally Invasive Lateral Anterior Column Realignment for Adult Spinal Deformity.

BACKGROUND: Development of proximal junctional kyphosis (PJK) after correction of adult spinal deformity (ASD) undermines sagittal alignment. Minimally invasive anterior column realignment (ACR) is a powerful tool for correction of ASD; however, long-term PJK rates are unknown. OBJECTIVE: To characterize PJK after utilization of ACR in ASD correction. METHODS: A retrospective multi-institution cohort analysis per STROBE criteria was conducted of all patients who underwent lateral lumbar interbody fusion (LLIF) or ACR for ASD from 2010 to 2015. All patients obtained preoperative and follow-up upright radiographs, assessing spinal alignment and development of PJK. Patients without proper imaging or minimum 1-yr follow-up were excluded. RESULTS: A total of 73 of 112 patients who underwent either LLIF or ACR for ASD met inclusion criteria. Mean follow-up was 22.8 mo. There was significant improvement of all spinopelvic parameters. Overall, PJK and proximal junctional failure (PJF) rates were 20.5% and 11%, respectively. The incidence of PJK increased with greater corrective surgery (0% LLIF, 30% ACR, 42.9% ACR + posterior column osteotomy (PCO); P < .001). PJF rates increased (0% LLIF, 11% ACR, 40% ACR + PCO; P = .005). Risk factors included location of the upper-instrumented vertebra at T10-L1 vs L2-L4 (P = .007), age (P = .029), severity of ASD, and overcorrection of sagittal imbalance. CONCLUSION: The incidence of PJK after minimally invasive ACR is slightly lower than reported after open surgery but greater than in LLIF only and increases with PCO utilization. The PJK rate increases when crossing the TL junction, sagittal imbalance severity, and overcorrection. Elderly patients are at an increased risk, suggesting need for age appropriate correction goals.

Limitations and complications of minimally invasive spinal surgery in adult deformity.

Minimally invasive spine (MIS) surgery has rapidly progressed from simple short segment fusions to large adult deformity corrections, with radiographic and clinical outcomes as good as those of open surgery. Anterior longitudinal ligament release (ALLR) and anterior column realignment (ACR) have been key advancements in the ability to correct deformity using MIS techniques. However, patient selection and appropriate preoperative workup is critical to obtain good outcomes and for complication avoidance. Despite favorable outcomes in spinal deformity surgery, MIS techniques are limited in (I) pronounced cervical or thoracic deformity; (II) patients with prior fusion mass; and (III) severe sagittal imbalance necessitating Schwab 5 osteotomy or higher. Guidelines for proper patient selection are needed to guide MIS spine surgeons in choosing the right candidate.