The authors present 2 cases of far-lateral lumbar disc herniations treated surgically via an extreme-lateral transpsoas approach. The procedure was performed using the MaXcess minimally invasive retractor system to access and successfully remove the disc fragments without complication. To the authors' knowledge, these are the first reported cases of using a minimally invasive retroperitoneal approach for the treatment of far-lateral disc herniations.
Ricky Madhok and Adam S. Kanter
Simon Morr and Adam S. Kanter
The minimally destructive lateral transpsoas approach to the spine has been used in the treatment of various lumbar spinal pathologies. Approach-specific complications have been reported due to the unique surgical corridor and lateral anatomical structures. The authors report a case of complex regional pain syndrome (CRPS) following interbody cage placement utilizing the lateral lumbar transpsoas approach. A review of the literature is discussed. Further clarification of the mechanism of CRPS and its treatments remains crucial for the fine-tuning of novel surgical techniques and complication avoidance during the development of these techniques.
Alik S. Widge, Nestor D. Tomycz and Adam S. Kanter
Acute cauda equina syndrome can occur due to a variety of causes. Inferior vena cava (IVC) thrombosis has been reported as the causal source of this phenomenon twice in the relevant literature, both cases of which presented in a form complete with a component of bowel and/or bladder dysfunction. The authors report an atypical case of cauda equina syndrome in a patient in a hypercoagulable state with an extensive IVC thrombosis, resulting in acute paraparesis in the absence of incontinence or perineal anesthesia. An increasing number of prophylactic and/or therapeutic IVC filters placed in the perioperative period should engender an increased clinical suspicion for IVC thrombosis in patients presenting with acute paraparesis.
Thoracolumbar spinal deformity
Christopher I. Shaffrey
H. Michael Keyoung, Adam S. Kanter and Praveen V. Mummaneni
✓There are many potential risks associated with spinal deformity correction procedures including transient and/or permanent neurological deficits. Typically, neurological deficits caused by the surgical correction of spinal kyphosis occur acutely during surgery or immediately after surgery. Delayed postoperative neurological deficits are extremely rare.
The authors report a case of delayed neurological deficit that occurred 48 hours after surgical correction of thoracic hyperkyphosis. An 18-year-old man with myotonic dystrophy presented with a 110° T7–L1 kyphosis. The patient underwent an uneventful two-stage correction procedure of the hyperkyphotic deformity. First, anterior discectomies and fusion were performed from T-7 to L-1 using rib autograft, and all segmental vessels were preserved. Subsequently, on the same day, the patient underwent posterior Smith–Petersen osteotomies and T7–L2 pedicle screw fixation. Intact somatosensory and motor evoked potentials were maintained throughout both operations. Postoperatively, he remained neurologically intact without sequelae for nearly 48 hours. On postoperative Day 2, the patient developed delayed monoplegia of the left leg and sensory level loss below T-10.
Medical management enabled complete reversal of the patient's monoplegia and sensory loss. At 2-year follow-up, the patient had no adverse neurological sequelae.
In this case, a delayed postoperative neurological deficit occurred following spinal hyperkyphosis correction. The authors discuss the possible etiological mechanisms behind this complication and suggest strategies for its management.
Presented at the 2018 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves
Nitin Agarwal, Andrew Faramand, Nima Alan, Zachary J. Tempel, D. Kojo Hamilton, David O. Okonkwo and Adam S. Kanter
Elderly patients, often presenting with multiple medical comorbidities, are touted to be at an increased risk of peri- and postoperative complications following spine surgery. Various minimally invasive surgical techniques have been developed and employed to treat an array of spinal conditions while minimizing complications. Lateral lumbar interbody fusion (LLIF) is one such approach. The authors describe clinical outcomes in patients over the age of 70 years following stand-alone LLIF.
A retrospective query of a prospectively maintained database was performed for patients over the age of 70 years who underwent stand-alone LLIF. Patients with posterior segmental fixation and/or fusion were excluded. The preoperative and postoperative values for the Oswestry Disability Index (ODI) were analyzed to compare outcomes after intervention. Femoral neck t-scores were acquired from bone density scans and correlated with the incidence of graft subsidence.
Among the study cohort of 55 patients, the median age at the time of surgery was 74 years (range 70–87 years). Seventeen patients had at least 3 medical comorbidities at surgery. Twenty-three patients underwent a 1-level, 14 a 2-level, and 18 patients a 3-level or greater stand-alone lateral fusion. The median estimated blood loss was 25 ml (range 5–280 ml). No statistically significant relationship was detected between volume of blood loss and the number of operative levels. The median length of hospital stay was 2 days (range 1–4 days). No statistically significant relationship was observed between the length of hospital stay and age at the time of surgery. There was one intraoperative death secondary to cardiac arrest, with a mortality rate of 1.8%. One patient developed a transient femoral nerve injury. Five patients with symptomatic graft subsidence subsequently underwent posterior instrumentation. A lower femoral neck t-score < −1.0 correlated with a higher incidence of graft subsidence (p = 0.006). The mean ODI score 1 year postoperatively of 31.1 was significantly (p = 0.003) less than the mean preoperative ODI score of 46.2.
Stand-alone LLIF can be safely and effectively performed in the elderly population. Careful evaluation of preoperative bone density parameters should be employed to minimize risk of subsidence and need for additional surgery. Despite an association with increased comorbidities, age alone should not be a deterrent when considering stand-alone LLIF in the elderly population.
Rob Dickerman, Julie Williamson and Matthew Bennett
Nitin Agarwal, Andrew Faramand, Johanna Bellon, Jeffrey Borrebach, D. Kojo Hamilton, David O. Okonkwo and Adam S. Kanter
The Clinician and Group Consumer Assessment of Healthcare Providers and Systems (CG-CAHPS) is a standardized patient experience survey that is used to evaluate the quality of care delivered by physicians. The authors sought to determine which factors influenced CG-CAHPS scores for spine surgery, and compare them to their cranial-focused cohorts.
A retrospective study of prospectively obtained data was performed to evaluate CG-CAHPS scores. Between May 2013 and May 2017, all patients 18 years of age or older with an outpatient encounter with a neurosurgeon (5 spine-focused neurosurgeons and 20 cranial-focused neurosurgeons) received a CG-CAHPS survey. Three domains were assessed: overall physician rating, likelihood to recommend, and physician communication. Statistical analyses were performed using chi-square tests.
Seven thousand four hundred eighty-five patient surveys (2319 spine and 5166 cranial) were collected from patients presenting to the outpatient offices of an attending neurosurgeon. Analysis of the overall physician rating showed that 81.1% of spine neurosurgeons received a “top-box” score (answers of “yes, definitely”), whereas 86.2% of cranial neurosurgeons received a top-box response (p < 0.001). A similar difference was observed with the domains of “likelihood to recommend” and “physician communication.” Overall physician rating was also significantly influenced by the general and mental health of the patients surveyed (p < 0.001). For spine surgeons seeing patients at more than one facility, the scores with respect to location were also significantly different in all domains for each individual provider (p < 0.001).
Overall, spine-focused neurosurgeon ratings differed significantly from those of cranial-focused neurosurgical subspecialty providers. Office location also affected provider ratings for spine neurosurgeons. These results suggest that physician ratings obtained via patient experience surveys may be representative of factors aside from just the quality of physician care provided. This information should be considered as payers, government, and health systems design performance programs based on patient experience scores.
Zachary J. Tempel, Michael M. McDowell, David M. Panczykowski, Gurpreet S. Gandhoke, D. Kojo Hamilton, David O. Okonkwo and Adam S. Kanter
Lateral lumbar interbody fusion (LLIF) is a less invasive surgical option commonly used for a variety of spinal conditions, including in high-risk patient populations. LLIF is often performed as a stand-alone procedure, and may be complicated by graft subsidence, the clinical ramifications of which remain unclear. The aim of this study was to characterize further the sequelae of graft subsidence following stand-alone LLIF.
A retrospective review of prospectively collected data was conducted on consecutive patients who underwent stand-alone LLIF between July 2008 and June 2015; 297 patients (623 levels) met inclusion criteria. Imaging studies were examined to grade graft subsidence according to Marchi criteria, and compared between those who required revision surgery and those who did not. Additional variables recorded included levels fused, DEXA (dual-energy x-ray absorptiometry) T-score, body mass index, and routine demographic information. The data were analyzed using the Student t-test, chi-square analysis, and logistic regression analysis to identify potential confounding factors.
Of 297 patients, 34 (11.4%) had radiographic evidence of subsidence and 18 (6.1%) required revision surgery. The median subsidence grade for patients requiring revision surgery was 2.5, compared with 1 for those who did not. Chi-square analysis revealed a significantly higher incidence of revision surgery in patients with high-grade subsidence compared with those with low-grade subsidence. Seven of 18 patients (38.9%) requiring revision surgery suffered a vertebral body fracture. High-grade subsidence was a significant predictor of the need for revision surgery (p < 0.05; OR 12, 95% CI 1.29–13.6), whereas age, body mass index, T-score, and number of levels fused were not. This relationship remained significant despite adjustment for the other variables (OR 14.4; 95% CI 1.30–15.9).
In this series, more than half of the patients who developed graft subsidence following stand-alone LLIF required revision surgery. When evaluating patients for LLIF, supplemental instrumentation should be considered during the index surgery in patients with a significant risk of graft subsidence.
Russ P. Nockels, Christopher I. Shaffrey, Adam S. Kanter, Syed Azeem and Julie E. York
Instability of the occipitocervical junction may result from degenerative disease, infection, tumor, and trauma. Surgical stabilization involving screw fixation and rigid implants has been found to be biomechanically superior to wire-based implants. To evaluate the long-term results in a large and diverse patient population, the authors prospectively studied a consecutive group of 69 patients.
All patients underwent occipitocervical fusion in which rigid posterior instrumentation included either plates or rods and screws. Patients ranged in age from 11 to 90 years (mean 51.4 years); there were 34 female and 35 male patients. The mean follow-up duration was 37 months (range 6–66 months). Fifty-seven (83%) of the 69 patients had long-standing occipitocervical anomalies, whereas the remainder presented with acute instability. Basilar invagination was present in 20 patients.
Correction of a severe cervical kyphotic deformity was accomplished in six patients. There were no fatalities or medical complications associated with the procedures. During the follow-up period, 87% of the patients exhibited improvement in their myelopathic symptoms; in 13% the symptoms were unchanged. Complications were minimal. Stability was demonstrated on flexion/extension studies in all cases. There were no treatment-related deaths, although four patients died within the follow-up period, all due to progression of metastatic disease.
The authors found that rigid internal fixation of the occipitocervical complex was safe, effective, and technically possible for spine surgeons familiar with occipital bone anatomy and lateral mass fixation.