Robotic versus nonrobotic sacroiliac joint fusion.

OBJECTIVE: Robot-assisted pedicle screw placement in spinal fusion has been well studied. However, few studies have evaluated robot-assisted sacroiliac joint (SIJ) fusion. The aim of this study was to compare surgical characteristics, accuracy, and complications between robot-assisted and fluoroscopically guided SIJ fusion. METHODS: A retrospective review of 110 patients with 121 SIJ fusions done at a single academic institution was conducted from 2014 to 2023. Inclusion criteria included adult age and a robot- or fluoroscopically guided approach to SIJ fusion. Patients were excluded if the SIJ fusion was part of a longer fusion construct, not minimally invasive, and/or had missing data. Demographics, approach type (robotic vs fluoroscopic), operative time, estimated blood loss (EBL), number of screws, intraoperative complications, 30-day complications, number of intraoperative fluoroscopic images (as a surrogate for radiation exposure), implant placement accuracy, and pain status at the first follow-up were recorded. Primary endpoints were SIJ screw placement accuracy and complications. Secondary endpoints were operative time, radiation exposure, and pain status at the first follow-up. RESULTS: Ninety patients were included who underwent a total of 101 SIJ fusions, of which 78 were robotic and 23 were fluoroscopic. The mean age of the cohort at the time of surgery was 55.9 ± 13.8 years; 46 patients were females (51.1%). No difference was found in screw placement accuracy between robotic and fluoroscopic fusion (1.3% vs 8.7%, p = 0.06). Chi-square analysis of robotic versus fluoroscopic fusion found no difference in the presence of 30-day complications (p = 0.62). Mann-Whitney U-test analysis found that robotic fusion had a significantly longer operative time than fluoroscopic fusion (72.0 vs 61.0 minutes, p = 0.01); however, robot-assisted fusions involved significantly lower radiation exposure (26.7 vs 187.4 fluoroscopic images, p < 0.001). No difference in EBL was noted (p = 0.17). No intraoperative complications were present in this cohort. Subgroup analysis comparing the 23 most recent robotic cases against the 23 fluoroscopic cases found that robotic fusion still was associated with significantly longer operative times than fluoroscopic fusion (74.0 ± 26.4 vs 61.0 ± 14.9 minutes, respectively; p = 0.047). CONCLUSIONS: SIJ screw placement accuracy did not significantly differ between robot-assisted and fluoroscopic SIJ fusion. Complications overall were low and similar between the two groups. The operative time was longer with robotic assistance, but there was markedly less radiation exposure to the surgeon and staff.

Bone metastasis from glioblastoma: a systematic review.

INTRODUCTION: Glioblastoma (GBM) is a devastating disease with poor overall survival. Despite the common occurrence of GBM among primary brain tumors, metastatic disease is rare. Our goal was to perform a systematic literature review on GBM with osseous metastases and understand the rate of metastasis to the vertebral column as compared to the remainder of the skeleton, and how this histology would fit into our current paradigm of treatment for bone metastases. METHODS: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-compliant literature search was performed using the PubMed database from 1952 to 2021. Search terms included "GBM", "glioblastoma", "high-grade glioma", "bone metastasis", and "bone metastases". RESULTS: Of 659 studies initially identified, 67 articles were included in the current review. From these 67 articles, a total of 92 distinct patient case presentations of metastatic glioblastoma to bone were identified. Of these cases, 58 (63%) involved the vertebral column while the remainder involved lesions within the skull, sternum, rib cage, and appendicular skeleton. CONCLUSION: Metastatic dissemination of GBM to bone occurs. While the true incidence is unknown, workup for metastatic disease, especially involving the spinal column, is warranted in symptomatic patients. Lastly, management of patients with GBM vertebral column metastases can follow the International Spine Oncology Consortium two-step multidisciplinary algorithm for the management of spinal metastases.

The impact of age on approach-related complications with navigated lateral lumbar interbody fusion.

OBJECTIVE: Age is known to be a risk factor for increased complications due to surgery. However, elderly patients can gain significant quality-of-life benefits from surgery. Lateral lumbar interbody fusion (LLIF) is a minimally invasive procedure that is commonly used to treat degenerative spine disease. Recently, 3D navigation has been applied to LLIF. The purpose of this study was to determine whether there is an increased complication risk in the elderly with navigated LLIF. METHODS: Patients who underwent 3D-navigated LLIF for degenerative disease from 2014 to 2019 were included in the analysis. Patients were divided into elderly and nonelderly groups, with those 65 years and older categorized as elderly. Ninety-day medical and surgical complications were recorded. Patient and surgical characteristics were compared between groups, and multivariate regression analysis was used to determine independent risk factors for complication. RESULTS: Of the 115 patients included, 56 were elderly and 59 were nonelderly. There were 15 complications (25.4%) in the nonelderly group and 10 (17.9%) in the elderly group, which was not significantly different (p = 0.44). On multivariable analysis, age was not a risk factor for complication (p = 0.52). However, multiple-level LLIF was associated with an increased risk of approach-related complication (OR 3.58, p = 0.02). CONCLUSIONS: Elderly patients do not appear to experience higher rates of approach-related complications compared with nonelderly patients undergoing 3D navigated LLIF. Rather, multilevel surgery is a predictor for approach-related complication.

The feasibility of computer-assisted 3D navigation in multiple-level lateral lumbar interbody fusion in combination with posterior instrumentation for adult spinal deformity.

OBJECTIVE: The lateral lumbar interbody fusion (LLIF) technique is used to treat many common spinal degenerative pathologies including kyphoscoliosis. The use of spinal navigation for LLIF has not been broadly adopted, especially in adult spinal deformity. The purpose of this study was to evaluate the feasibility as well as the intraoperative and navigation-related complications of computer-assisted 3D navigation (CaN) during multiple-level LLIF for spinal deformity. METHODS: Retrospective analysis of clinical and operative characteristics was performed for all patients > 18 years of age who underwent multiple-level CaN LLIF combined with posterior instrumentation for adult spinal deformity at the University of Michigan between 2014 and 2020. Intraoperative CaN-related complications, LLIF approach-related postoperative complications, and medical postoperative complications were assessed. RESULTS: Fifty-nine patients were identified. The mean age was 66.3 years (range 42-83 years) and body mass index was 27.6 kg/m2 (range 18-43 kg/m2). The average coronal Cobb angle was 26.8° (range 3.6°-67.0°) and sagittal vertical axis was 6.3 cm (range -2.3 to 14.7 cm). The average number of LLIF and posterior instrumentation levels were 2.97 cages (range 2-5 cages) and 5.78 levels (range 3-14 levels), respectively. A total of 6 intraoperative complications related to the LLIF stage occurred in 5 patients. Three of these were CaN-related and occurred in 2 patients (3.4%), including 1 misplaced lateral interbody cage (0.6% of 175 total lateral cages placed) requiring intraoperative revision. No patient required a return to the operating room for a misplaced interbody cage. A total of 12 intraoperative complications related to the posterior stage occurred in 11 patients, with 5 being CaN-related and occurring in 4 patients (6.8%). Univariate and multivariate analyses revealed no statistically significant risk factors for intraoperative and CaN-related complications. Transient hip weakness and numbness were found to be in 20.3% and 22.0% of patients, respectively. At the 1-month follow-up, weakness was observed in 3.4% and numbness in 11.9% of patients. CONCLUSIONS: Use of CaN in multiple-level LLIF in the treatment of adult spinal deformity appears to be a safe and effective technique. The incidence of approach-related complications with CaN was 3.4% and cage placement accuracy was high.

The impact of blood pressure management after spinal cord injury: a systematic review of the literature.

OBJECTIVE Spinal cord injury (SCI) results in significant morbidity and mortality. Improving neurological recovery by reducing secondary injury is a major principle in the management of SCI. To minimize secondary injury, blood pressure (BP) augmentation has been advocated. The objective of this study was to review the evidence behind BP management after SCI. METHODS This systematic review was conducted following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Using the PubMed database, the authors identified studies that investigated BP management after acute SCI. Information on BP goals, duration of BP management, vasopressor selection, and neurological outcomes were analyzed. RESULTS Eleven studies that met inclusion criteria were identified. Nine studies were retrospective, and 2 were single-cohort prospective investigations. Of the 9 retrospective studies, 7 reported a goal mean arterial pressure (MAP) of higher than 85 mm Hg. For the 2 prospective studies, the MAP goals were higher than 85 mm Hg and higher than 90 mm Hg. The duration of BP management varied from more than 24 hours to 7 days in 6 of the retrospective studies that reported the duration of treatment. In both prospective studies, the duration of treatment was 7 days. In the 2 prospective studies, neurological outcomes were stable to improved with BP management. The retrospective studies, however, were contradictory with regard to the correlation of BP management and outcomes. Dopamine, norepinephrine, and phenylephrine were the agents that were frequently used to augment BP. However, more complications have been associated with dopamine use than with the other vasopressors. CONCLUSIONS There are no high-quality data regarding optimal BP goals and duration in the management of acute SCI. Based on the highest level of evidence available from the 2 prospective studies, MAP goals of 85-90 mm Hg for a duration of 5-7 days should be considered. Norepinephrine for cervical and upper thoracic injuries and phenylephrine or norepinephrine for mid- to lower thoracic injuries should be considered.

Recovery of Shoulder, Elbow, and Forearm Movement After Nerve Reconstruction for Neonatal Brachial Plexus Palsy.

BACKGROUND AND OBJECTIVES: There is a relative dearth of published data with respect to recovery of upper extremity movement after nerve reconstruction for neonatal brachial plexus palsy (NBPP). This study aimed to demonstrate long-term recovery of active range of motion (AROM) at the shoulder, elbow, and forearm after nerve reconstruction for NBPP and to compare that with patients managed nonoperatively. METHODS: We interrogated a prospectively collected database of all patients evaluated for NBPP at a single institution from 2005 to 2020. AROM measurements for shoulder, elbow, and forearm movements were collected at every visit up to 5 years of follow-up and normalized between 0 and 1. We used generalized estimated equations to predict AROM for each movement within local age windows over 5 years and compared the operative and nonoperative cohorts at each age interval. RESULTS: In total, >13 000 collected datapoints representing 425 conservatively and 99 operatively managed children were included for analysis. At 5 years, absolute recovery of AROM after nerve reconstruction was ∼50% for shoulder abduction and forward flexion, ∼65% for shoulder external rotation, and ∼75% for elbow flexion and forearm supination, with ∼20% loss of elbow extension AROM. Despite more limited AROM on presentation for the operative cohort, at 5 years, there was no significant difference between the groups in AROM for shoulder external rotation, elbow extension, or forearm supination, and, in Narakas grade 1-2 injury, shoulder abduction and forward flexion. CONCLUSION: We demonstrate recovery of upper extremity AROM after nerve surgery for NBPP. Despite more severe presenting injury, operative patients had similar recovery of AROM when compared with nonoperative patients for shoulder external rotation, elbow extension, forearm supination, and, for Narakas grade 1-2 injury, shoulder abduction and forward flexion.

Virtual Reality-Enabled Resident Education of Lateral-Access Spine Surgery.

OBJECTIVE: Lateral-access spine surgery has many benefits, but adoption has been limited by a steep learning curve. Virtual reality (VR) is gaining popularity and lends itself as a useful tool in enhancing neurosurgical resident education. We thus sought to assess whether VR-based simulation could enhance the training of neurosurgery residents in lateral spine surgery. METHODS: Neurosurgery residents completed a VR-based lateral spine module on lateral patient positioning and performing lateral lumbar interbody fusion using the PrecisionOS VR system on the Meta Quest 2 headset. Simulation occurred 1×/week every other week for a total of 3 simulations over 6 weeks. Pre- and postintervention surveys as well as intrasimulation performance metrics were assessed over time. RESULTS: The majority of resident participants showed improvement in performance scores, including an automated PrecisionOS precision score, number of radiographs used within the simulation, and time to completion. All participants showed improvement in comfort with anatomic landmarks for lateral access surgery, confidence performing lateral surgery without direct supervision, and assessing fluoroscopy in spine surgery for hardware placement and image interpretation. Participant perception on the utility of VR as an educational tool also improved. CONCLUSIONS: VR-based simulation enhanced neurosurgical residents' ability to understand lateral access surgery. Immersive surgical simulation resulted in improved resident confidence with surgical technique and workflow, perceived improvement in anatomical knowledge, and simulation performance scores. Trainee perceptions on virtual simulation and training as a curriculum supplement also improved following completion of VR training.

Computed tomography assessment of robotic versus fluoroscopic implant accuracy in sacroiliac joint fusion.

OBJECTIVE: Computed tomography is considered the gold-standard imaging tool to evaluate spinal implant accuracy. However, there are no studies that evaluate the accuracy of robotic sacroiliac joint (SIJ) implant placement using CT to date. The aim of this study was to compare the accuracy of implant placement on CT between robotic and fluoroscopic navigation for SIJ fusion and the subsequent complications and clinical outcomes of suboptimally placed screws. METHODS: A retrospective analysis of SIJ fusions utilizing either robotic or fluoroscopic guidance at a single institution was conducted from 2014 to 2023. Implant placement accuracy was evaluated on intra- or postoperative CT. Primary endpoints were SIJ screw placement accuracy and complications. Secondary endpoints were pain status at the first and second follow-ups and rates of 2-year revision surgery. Statistical analysis was performed using chi-square tests. RESULTS: Sixty-nine patients who underwent 78 SIJ fusions were included, of which 63 were robotic and 15 were fluoroscopic. The mean age of the cohort at the time of surgery was 55.9 ± 14.2 years, and 35 patients (50.7%) were female. There were 135 robotically placed and 34 fluoroscopically placed implants. A significant difference was found in implant placement accuracy between robotic and fluoroscopic fusion (97.8% vs 76.5%, p < 0.001). When comparing optimal versus suboptimal implant placement, no difference was found in the presence of 30-day complications (p = 0.98). No intraoperative complications were present in this cohort. No difference was found in subjective pain status at the first (p = 0.69) and second (p = 0.45) follow-ups between optimal and suboptimal implant placement. No patients underwent 2-year revision surgery. CONCLUSIONS: Use of robotic navigation was significantly more accurate than the use of fluoroscopic navigation for SIJ implant placement. Complications overall were low and not different between optimally and suboptimally placed implants. Suboptimally placed implants did not differ in degree of subjective pain improvement or rates of revision surgery postoperatively.

Supraclavicular approach for neonatal brachial plexus palsy.

Neonatal brachial plexus palsy describes injury to the brachial plexus in the perinatal period, resulting in motor and sensory deficits of the upper arm. Nerve reconstruction, including graft repair and nerve transfers, can be used to restore function in patients whose injury does not respond to conservative management. Despite the availability of these techniques, 30%-40% of children have lifelong disability, reflecting a 10-fold underutilization of surgery. Here, the authors demonstrate a supraclavicular approach for brachial plexus exploration, as well as a spinal accessory to suprascapular nerve transfer for restoration of shoulder abduction and external rotation. The video can be found here: https://stream.cadmore.media/r10.3171/2022.10.FOCVID22109.

Alternatives to DEXA for the assessment of bone density: a systematic review of the literature and future recommendations.

OBJECTIVE: Osteoporosis has significant implications in spine fusion surgery, for which reduced spinal bone mineral density (BMD) can result in complications and poorer outcomes. Currently, dual-energy x-ray absorptiometry (DEXA) is the gold standard for radiographic diagnosis of osteoporosis, although DEXA accuracy may be limited by the presence of degenerative spinal pathology. In recent years, there has been an evolving interest in using alternative imaging, including CT and MRI, to assess BMD. In this systematic review of the literature, the authors assessed the use and effectiveness of MRI, opportunistic CT (oCT), and quantitative CT (qCT) to measure BMD. METHODS: In accordance with the PRISMA guidelines, the authors conducted a systematic search for articles posted on PubMed between the years 2000 and 2022 by using the keywords "opportunistic CT, quantitative CT, MRI" AND "bone density" AND "spine." Inclusion criteria consisted of articles written in English that reported studies pertaining to human or cadaveric subjects, and studies including a measure of spinal BMD. Articles not related to spinal BMD, osteoporosis, or spinal surgery or reports of studies that did not include the use of spinal MRI or CT were excluded. Key study outcomes were extracted from included articles, and qualitative analysis was subsequently performed. RESULTS: The literature search yielded 302 articles. Forty-two articles reported studies that met the final inclusion criteria. Eighteen studies utilized MRI protocols to correlate spinal BMD with vertebral bone quality scores, M-scores, and quantitative perfusion markers. Eight studies correlated oCT with spinal BMD, and 16 studies correlated qCT with spinal BMD. With oCT and qCT imaging, there was consensus that Hounsfield unit (HU) values > 160 demonstrated significant reduction in risk of osteoporosis, whereas HU values < 110 were significantly correlated with osteoporosis. CONCLUSIONS: Osteoporosis is increasingly recognized as a significant risk factor for complications after spinal fusion surgery. Consequently, preoperative assessment of BMD is a critical factor to consider in planning surgical treatment. Although DEXA has been the gold standard for BMD measurement, other imaging modalities, including MRI, oCT, and qCT, appear to be viable alternatives and may offer cost and time savings.

Defining postoperative C5 palsy and recovery: a systematic review.

OBJECTIVE: Postoperative C5 palsy (C5P) is a well-recognized and often-delayed complication of cervical spine surgery. Most patients recover within 6 months of onset, but the prognosis of severe cases is poor. The clinical significance and natural history of mild versus severe C5P appear to differ substantially, but palsy severity and recovery have been poorly characterized in the literature. METHODS: Owing to the varying prognoses and expanding treatment options such as nerve transfer surgery to reconstruct the C5 myotome, this systematic review attempted to describe how C5P severity is classified and how C5P and its recovery are defined, with the aim of proposing a postoperative C5P scale to support clinical decision-making. PubMed was searched for articles in English published since 2000 that offer a clear definition of postoperative C5P or its recovery. Only articles reporting exclusively on C5 palsy for patients undergoing surgery for degenerative disease were included. A single reviewer screened titles and abstracts and reviewed the full text of relevant articles, with consultation as needed from a second reviewer. Data collected included postoperative C5P definitions, classification of C5P severity, and definition and/or classification of C5P recovery. Qualitative analysis was performed. RESULTS: Full-text reviews were conducted of 98 of 272 articles identified and screened, and 43 met the inclusion criteria. Postoperative C5P was most commonly defined as a reduction in deltoid muscle strength by ≥ 1 grade using manual muscle testing (MMT), with potential biceps involvement also noted by some studies. The few studies that stratified C5P on the basis of severity unanimously characterized severe C5P as MMT grade ≤ 2. Nine studies reported on C5P recovery. Deltoid muscle strength improvement of MMT grade 5 commonly defined complete recovery, with no MMT improvement considered partial recovery. CONCLUSIONS: This review identified clear discrepancies in the definitions of C5P and its recovery, leading to heterogeneity in its evaluation and management. With the emergence of therapeutic procedures for severe C5P, standardization of the definitions of C5P and its recovery is critical. The authors propose MMT grades of 4, 3, and ≤ 2 to classify C5P as mild, moderate, and severe, respectively, and grades of 5, 4, and 3 to classify recovery as complete, sufficient, and useful, respectively.

Impact of Timing of Primary Nerve Surgery on Shoulder, Forearm, and Elbow Recovery in Neonatal Brachial Plexus Palsy.

BACKGROUND AND OBJECTIVES: Neonatal brachial plexus palsy (NBPP) almost universally affects movement at the shoulder, elbow, and forearm. Timing of nerve reconstruction surgery to optimize long-term outcomes remains unknown. This study aimed to determine if timing of nerve reconstruction affects long-term recovery of an active range of motion (AROM) at the shoulder, elbow, and forearm in NBPP. METHODS: We interrogated a prospectively collected database of all patients with NBPP who underwent primary nerve surgery at a single tertiary referral center between 2005 and 2020. The cohort was divided into those who underwent surgery at ≤6 or >6 months old and ≤9 or >9 months old. AROM for shoulder abduction, forward flexion, and external rotation, elbow flexion and extension, and forearm supination were collected at each visit. RESULTS: Ninety-nine children were included in the analysis; 28 underwent surgery at ≤6 months old, 71 at >6 months, 74 at ≤9 months, and 25 at >9 months. There was no difference in AROM at 5 years for any of the movements between the ≤6- and >6-month groups. The ≤9-month group had significantly better shoulder forward flexion and elbow extension AROM than the >9-month group at a 5-year follow-up and better forearm supination at up to a 15-year follow-up. Patients who presented earlier were more likely to have earlier operations. CONCLUSION: Surgery before 9 months may improve long-term upper extremity recovery in NBPP. Early referral should be encouraged to optimize timing of operative intervention.

How closely are outcome questionnaires correlated to patient satisfaction after cervical spine surgery for myelopathy?

OBJECTIVE: Patient-reported outcomes (PROs) have become the standard means to measure surgical outcomes. Insurers and policy makers are also increasingly utilizing PROs to assess the value of care and measure different aspects of a patient's condition. For cervical myelopathy, it is currently unclear which outcome measure best reflects patient satisfaction. In this investigation, the authors evaluated patients treated for cervical myelopathy to determine which outcome questionnaires best correlate with patient satisfaction. METHODS: The Quality Outcomes Database (QOD), a prospectively collected multi-institutional database, was used to retrospectively analyze patients undergoing surgery for cervical myelopathy. The North American Spine Society (NASS) satisfaction index, Neck Disability Index (NDI), numeric rating scales for neck pain (NP-NRS) and arm pain (AP-NRS), EQ-5D, and modified Japanese Orthopaedic Association (mJOA) scale were evaluated. RESULTS: The analysis included 1141 patients diagnosed with myelopathy, of whom 1099 had an NASS satisfaction index recorded at any of the follow-up time points. Concomitant radiculopathy was an indication for surgery in 368 (33.5%) patients, and severe neck pain (NP-NRS ≥ 7) was present in 471 (42.8%) patients. At the 3-month follow-up, NASS patient satisfaction index scores were positively correlated with scores for the NP-NRS (r = 0.30), AP-NRS (r = 0.32), and NDI (r = 0.36) and negatively correlated with EQ-5D (r = -0.38) and mJOA (r = -0.29) scores (all p < 0.001). At the 12-month follow-up, scores for the NASS index were positively correlated with scores for the NP-NRS (r = 0.44), AP-NRS (r = 0.38), and NDI (r = 0.46) and negatively correlated with scores for the EQ-5D (r = -0.40) and mJOA (r = -0.36) (all p < 0.001). At the 24-month follow-up, NASS index scores were positively correlated with NP-NRS (r = 0.49), AP-NRS (r = 0.36), and NDI (r = 0.49) scores and negatively correlated with EQ-5D (r = -0.44) and mJOA (r = -0.38) scores (all p < 0.001). CONCLUSIONS: Neck pain was highly prevalent in patients with myelopathy. Notably, improvement in neck pain-associated disability rather than improvement in myelopathy was the most prominent PRO factor for patients. This finding may reflect greater patient concern for active pain symptoms than for neurological symptoms caused by myelopathy. As commercial payers begin to examine novel remuneration strategies for surgical interventions, thoughtful analysis of PRO measurements will have increasing relevance.

Intrathecal Medication From Pain Pump Caused Prolonged Alteration in Mental Status Following Decompression of Severe Spinal Stenosis.

Intrathecal drug delivery (IDD) has multiple indications, including chronic pain, spasticity, and spinal cord injury. Patients with an IDD device implanted who are undergoing decompressive spinal surgery may be at risk for intrathecal (IT) drug overdose in the perioperative setting. The present report describes a patient with an IDD device who underwent elective spinal surgery that was complicated by prolonged, severe alteration in mental status over several days, requiring discontinuation of his IT medications. The patient eventually returned to his neurological baseline by postoperative day 14. In the setting of severe spinal stenosis cranially in relation to an IDD device, consideration for weaning IT medications prior to elective surgery is recommended to avoid potential IT overdose. Patients undergoing weaning should be monitored for signs and symptoms of medication withdrawal.

The impact of misplaced percutaneous iliac dynamic reference frame pins used during navigated spine surgery: incidence and outcomes.

OBJECTIVE: Image guidance requires placement of a dynamic reference frame (DRF), often either onto local spinous process or by freehand intraosseous DRF placement into the ilium via the posterior superior iliac spine (PSIS). There is a paucity of studies in the literature that describe the complications of intraosseous DRF placement. The aim of this study was to describe the radiographic location, prevalence and nature of complications, and long-term clinical outcomes of attempted DRF placement into the PSIS. METHODS: All lumbosacral spine surgical procedures performed between August 2019 and February 2021 at a single institution were queried, and operations in which a DRF was targeted to the PSIS were included. Patient demographic characteristics, indications for surgery, surgical outcomes, and complications were extracted. Intraoperative CT scans were reviewed by 2 independent researchers to determine the accuracy of DRF placement into the PSIS and to assess for DRF malposition. RESULTS: Of 497 lumbar spine operations performed between August 2019 and February 2021 by 4 surgeons, 85 utilized intraoperative navigation with a PSIS pin. Thirteen operations were excluded due to an inability to visualize the entirety of the pin on intraoperative CT. Of 72 DRFs evaluated, 77.8% had been correctly placed in the PSIS. Of the 22.2% of DRFs not placed into the PSIS, 11 entered the sacrum, 6 crossed the sacroiliac joint, and 2 were deep enough to enter the pelvis. Pain at the pin site was present in 4 patients, of whom 3 had resolution of pain at the last follow-up evaluation. There were no significant complications due to DRF placement: no sacral fractures, significant navigation errors, retroperitoneal hematomas, or neurological deficits. Over a mean ± SD follow-up period of 9 ± 5.2 months, there were no incidences of pin site infection. Interrater reliability between the reviewers was 95.8%. CONCLUSIONS: This was the first study to examine radiological and clinical outcomes after DRF placement in the PSIS. In this study, a majority of pins were correctly placed within the PSIS, although 22.2% of pins were malpositioned. There were no serious complications, and a majority of those patients with persistent pin site pain had resolution at last follow-up.

Optimal timing of referral for nerve transfer surgery for postoperative C5 palsy.

OBJECTIVE: Cervical nerve 5 palsy can occur following surgery for cervical spine pathology. The prognosis of C5 palsy is generally favorable, and most patients recover useful function. However, some patients do not recover useful strength. Nerve transfers are a potential effective treatment of postoperative severe C5 palsy. This study aimed to further delineate the natural history of recovery from postoperative C5 palsy, determine whether lack of recovery at specific time points predicts poor recovery prognosis, and thereby determine a reasonable time point for referral to a complex peripheral nerve specialist. METHODS: The authors conducted a retrospective review of 72 patients who underwent surgery for cervical spondylosis and stenosis complicated by C5 palsy. Medical Research Council (MRC) motor strength grades were recorded preoperatively; immediately postoperatively; at discharge; and at 2 weeks, 3 months, 6 months, and 12 months postoperatively. Univariate and multivariate logistic regression models were used to identify demographic and clinical risk factors associated with recovery of useful strength after severe C5 palsy. RESULTS: The mean patient age was 62.5 years, and 36.1% of patients were female. Thirty patients (41.7%) experienced severe C5 palsy with less than antigravity strength (MRC grade 2 or less) at discharge. Twenty-one (70%) of these patients recovered useful strength (MRC grade 3 or greater) at 12 months postoperatively, and 9 patients (30%) did not recover useful strength at 12 months. Of those patients with persistent severe C5 palsy at 3 months postoperatively, 50% recovered useful strength at 12 months. Of those patients with persistent severe C5 palsy at 6 months postoperatively, 25% recovered useful strength at 12 months. No patient with MRC grade 0 or 1 strength at 6 months postoperatively recovered useful strength. A history of diabetes was associated with the occurrence of severe C5 palsy. On multivariate analysis, female sex was associated with recovery of useful strength. CONCLUSIONS: Most patients with severe C5 palsy recover useful strength in their C5 myotome within 12 months of onset. However, at 3 months postoperatively, patients with persistent severe C5 palsy had only a 50% chance of recovering useful strength by 12 months. Lack of recovery of useful strength at 3 months postoperatively is a reasonable time point for referral to a complex peripheral nerve center to establish care and to determine candidacy for nerve transfer surgery if severe C5 palsy persists.

Syrinx regression after correction of iatrogenic kyphotic deformity: illustrative case.

BACKGROUND: Syringomyelia has a long-established association with pediatric scoliosis, but few data exist on the relationship of syringomyelia to pediatric kyphotic deformities. OBSERVATIONS: This report reviewed a unique case of rapid and sustained regression of syringomyelia in a 13-year-old girl after surgical correction of iatrogenic kyphotic deformity. LESSONS: In cases of syringomyelia associated with acquired spinal deformity, treatment of deformity to resolve an associated subarachnoid block should be considered because it may obviate the need for direct treatment of syrinx.