Initial United States experience with Medtronic Stealth Autoguide cranial robotic guidance platform.

OBJECTIVE: Stereotactic techniques play an important role in neurosurgery. The development of a miniaturized cranial robot with an efficient workflow and accurate surgical execution is an important step in a broader application of these techniques. Herein, the authors describe their experience with the Medtronic Stealth Autoguide miniaturized cranial robot. METHODS: A retrospective review of 75 cases from 2020 to 2022 was performed. The patients who had undergone surgery utilizing the Stealth Autoguide robot were analyzed for surgical indication and accuracy, operative time, and clinical outcome. The outcomes were defined as follows: for stereoelectroencephalography (SEEG), the electrode placement pattern that identified the seizure focus and did not require any revision or additional leads; for biopsy, the percentage of cases in which diagnostic tissue was obtained; and for laser interstitial thermal therapy (LITT), the percentage of cases in which laser fiber placement was adequate for ablation. Surgical complications were defined as any asymptomatic or symptomatic intracerebral hemorrhage, new neurological deficit, or need for electrode, laser fiber, or biopsy needle repositioning or revision. RESULTS: The Stealth Autoguide robot was utilized in 75 on-label cases, including 40 SEEG cases for seizure focus localization, 19 LITT cases, and 16 stereotactic biopsy cases. The mean real target error (RTE) at the entry was 1.48 ± 0.84 mm for biopsy, 1.36 ± 0.89 mm for Visualase laser fiber placement, and 1.24 ± 0.72 mm for SEEG. The mean RTE at the target was 1.56 ± 0.95 mm for biopsy needle placement, 1.42 ± 0.93 mm for Visualase laser fiber placement, and 1.31 ± 0.87 mm for SEEG electrode placement. The surgical time for unilateral SEEG cases took an average 52 minutes (average 6.5 mins/lead, average 8 electrodes). Bilateral SEEG cases took an average 105 minutes (average 7.5 mins/lead, average 14 electrodes). In the SEEG population, there were no revised or unsuccessful seizure localizations. For biopsy, diagnostic tissue was obtained in 100% of cases. For LITT, fiber placement was adequate for ablation in 100% of cases. There were no cases of symptomatic or asymptomatic intracerebral hemorrhage, and no cases required repositioning or replacement of the laser fiber, electrode, or biopsy needle. One patient experienced transient cranial nerve III palsy following laser ablation that resolved in 10 weeks. A failure of communication between the robotic platform and the Stealth Autoguide as a station required the cancellation of 1 procedure. CONCLUSIONS: The Medtronic Stealth Autoguide robot system is versatile across biopsy, SEEG, and laser ablation indications. Setup and surgical execution are efficient with a high degree of accuracy and consistency.

Thyroid hormone resuscitation after brain death in potential organ donors: A primer for neurocritical care providers and narrative review of the literature.

Solid organ transplantation has become a mainstay in the contemporary management of end-stage organ failures fueled by advances in immunosuppression, intensive care and surgical technology. Every year, a vast number of transplantable organs is lost on account of hemodynamic instability in potential brain-dead organ donors. Because of a growing organ shortage, measures that increase total donor supply pools are desperately needed. Thyroid hormone has been identified as an adjunctive therapy in donor management due to its potential for increasing organ supply and is currently endorsed by transplant organizations such as United Network for Organ Sharing (UNOS). Much of the evidence in support of thyroid hormone comes from level III studies showing greater donor survival and procurement rates. However, all prospective randomized studies to date have failed to corroborate any such benefit. Here, we describe the role of thyroid hormone in transplantation medicine and summarize data on its putative contributions to circulatory stability, organ yield and long-term graft function. At present, level I studies do not exist and many level II studies, which do not endorse its use, are of poor quality. Further research, particularly large-scale multi-center trials are therefore warranted to shed light on this matter.

A Novel Lumbar Motion Segment Classification to Predict Changes in Segmental Sagittal Alignment After Lateral Interbody Fixation.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: Lateral interbody fixation is being increasingly used for the correction of segmental sagittal parameters. One factor that affects postoperative correction is the resistance afforded by posterior hypertrophic facet joints in the degenerative lumbar spine. In this article, we describe a novel preoperative motion segment classification system to predict postoperative correction of segmental sagittal alignment after lateral lumbar interbody fusion. METHODS: Preoperative computed tomography scans were analyzed for segmental facet osseous anatomy for all patients undergoing lateral lumbar interbody fusion at 3 institutions. Each facet was assigned a facet grade (min = 0, max = 2), and the sum of the bilateral facet grades was the final motion segment grade (MSG; min = 0, max = 4). Preoperative and postoperative segmental lordosis was measured on standing lateral radiographs. Postoperative segmental lordosis was also conveyed as a percentage of the implanted graft lordosis (%GL). Simple linear regression was conducted to predict the postoperative segmental %GL according to MSG. RESULTS: A total of 36 patients with 59 operated levels were identified. There were 19 levels with MSG 0, 14 levels with MSG 1, 13 levels with MSG 2, 8 levels with MSG 3, and 5 levels with MSG 4. Mean %GL was 115%, 90%, 77%, 43%, and 5% for MSG 0 to 4, respectively. MSG significantly predicted postoperative %GL (P < .01). Each increase in MSG was associated with a 28% decrease in %GL. CONCLUSIONS: We propose a novel facet-based motion segment classification system that significantly predicted postoperative segmental lordosis after lateral lumbar interbody fusion.

Current Diagnosis and Management of Cervical Spondylotic Myelopathy.

STUDY DESIGN: Review. OBJECTIVES: Cervical spondylotic myelopathy (CSM) is a major cause of disability, particular in elderly patients. Awareness and understanding of CSM is imperative to facilitate early diagnosis and management. This review article addresses CSM with regard to its epidemiology, anatomical considerations, pathophysiology, clinical manifestations, imaging characteristics, treatment approaches and outcomes, and the cost-effectiveness of surgical options. METHODS: The authors performed an extensive review of the peer-reviewed literature addressing the aforementioned objectives. RESULTS: The clinical presentation and natural history of CSM is variable, alternating between quiescent and insidious to stepwise decline or rapid neurological deterioration. For mild CSM, conservative options could be employed with careful observation. However, surgical intervention has shown to be superior for moderate to severe CSM. The success of operative or conservative management of CSM is multifactorial and high-quality studies are lacking. The optimal surgical approach is still under debate, and can vary depending on the number of levels involved, location of the pathology and baseline cervical sagittal alignment. CONCLUSIONS: Early recognition and treatment of CSM, before the onset of spinal cord damage, is essential for optimal outcomes. The goal of surgery is to decompress the cord with expansion of the spinal canal, while restoring cervical lordosis, and stabilizing when the risk of cervical kyphosis is high. Further high-quality randomized clinical studies with long-term follow up are still needed to further define the natural history and help predict the ideal surgical strategy.

Rates of Seizure Freedom After Surgical Resection of Diffuse Low-Grade Gliomas.

OBJECTIVE: Patients with diffuse low-grade gliomas (DLGGs) typically present with seizures. We sought to review the neurosurgical literature for seizure outcome after resection of these tumors. METHODS: Using PubMed, we identified surgical series reporting seizure freedom rates for grade II astrocytoma, oligoastrocytoma, and oligodendroglioma. Inclusion criteria included seizure outcomes reported specifically for DLGGs and at least 10 patients with follow-up data. RESULTS: Twelve articles met the inclusion criteria. The median seizure-free rate after surgery in these patients was 71%, with an interquartile range of 64%-82%. In 10 studies, more than 60% of patients were seizure free. Studies used varying reporting times for seizure outcome determination. In the 6 studies that reported postoperative antiepileptic medication use, 5%-69% of seizure-free patients were weaned off these agents (median, 32%). The durability of seizure freedom has not been clearly studied to date. The most commonly reported prognostic factor for seizure freedom after resection was increasing extent of resection. CONCLUSIONS: Among articles reporting seizure outcomes after resection of DLGG, the median seizure-free rate was 71% (interquartile range, 64%-82%). Seizure freedom is likely associated with extent of resection.

Semitendinosus Graft for Interspinous Ligament Reinforcement in Adult Spinal Deformity.

Proximal junctional kyphosis is an increasingly recognized complication following long-segment posterior spinal fusion for adult spinal deformity. The authors describe a novel technique for interspinous ligament reinforcement at the proximal adjacent levels using a cadaveric semitendinosus tendon graft secured with an Ethibond No. 2 double filament (Ethicon, Somerville, New Jersey) via the Krackow suture weave. A retrospective review identified 4 patients who had received this graft. No proximal junctional kyphosis was seen at a mean short-term follow-up of 5.5 months. Interspinous ligament reinforcement at the proximal adjacent level with a cadaveric semitendinosus tendon graft is a feasible strategy for preventing proximal junctional kyphosis. [Orthopedics. 2017; 40(1):e206-e210.].

Complications associated with the Dynesys dynamic stabilization system: a comprehensive review of the literature.

The Dynesys dynamic stabilization system is an alternative to rigid instrumentation and fusion for the treatment of lumbar degenerative disease. Although many outcomes studies have shown good results, currently lacking is a comprehensive report on complications associated with this system, especially in terms of how it compares with reported complication rates of fusion. For the present study, the authors reviewed the literature to find all studies involving the Dynesys dynamic stabilization system that reported complications or adverse events. Twenty-one studies were included for a total of 1166 patients with a mean age of 55.5 years (range 39-71 years) and a mean follow-up period of 33.7 months (range 12.0-81.6 months). Analysis of these studies demonstrated a surgical-site infection rate of 4.3%, pedicle screw loosening rate of 11.7%, pedicle screw fracture rate of 1.6%, and adjacent-segment disease (ASD) rate of 7.0%. Of studies reporting revision surgeries, 11.3% of patients underwent a reoperation. Of patients who developed ASD, 40.6% underwent a reoperation for treatment. The Dynesys dynamic stabilization system appears to have a fairly similar complication-rate profile compared with published literature on lumbar fusion, and is associated with a slightly lower incidence of ASD.

Material Science in Cervical Total Disc Replacement.

Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation.

Implications of spinopelvic alignment for the spine surgeon.

The relation of the pelvis to the spine has previously been overlooked as a contributor to sagittal balance. However, it is now recognized that spinopelvic alignment is important to maintain an energy-efficient posture in normal and disease states. The pelvis is characterized by an important anatomic landmark, the pelvic incidence (PI). The PI does not change after adolescence, and it directly influences pelvic alignment, including the parameters of pelvic tilt (PT) and sacral slope (SS) (PI = PT 1 SS), overall sagittal spinal balance, and lumbar lordosis. In the setting of an elevated PI, the spineadapts with increased lumbar lordosis. To prevent or limit sagittal imbalance, the spine may also compensate with increased PT or pelvic retroversion to attempt to maintain anupright posture. Abnormal spinopelvic parameters contribute to multiple spinal conditions including isthmic spondylolysis, degenerative spondylolisthesis, deformity, and impact outcome after spinal fusion. Sagittal balance, pelvic incidence, and all spinopelvic parameters are easily and reliably measured on standing, full-spine (lateral) radiographs, and it is essential to accurately assess and measure these sagittal values to understand their potential role in the disease process, and to promote spinopelvic balance at surgery. In this article, we provide a comprehensive review of the literature regarding the implications of abnormal spinopelvic parameters and discuss surgical strategies for correction of sagittal balance. Additionally, the authors rate and critique the quality of the literature cited in a systematic review approach to give the reader an estimate of the veracity of the conclusions reached from these reports.

Novel application of pre-operative vertebral body embolization to reduce intraoperative blood loss during a three-column spinal osteotomy for non-oncologic spinal deformity.

Three column osteotomies (3CO) of the lumbar spine are powerful corrective procedures used in the treatment of kyphoscoliosis. Their efficacy comes at the cost of high reported complication rates, notably significant estimated blood loss (EBL). Previously reported techniques to reduce EBL have had modest efficacy. Here we describe a potential technique to decrease EBL during pedicle subtraction osteotomy (PSO) of the lumbar spine by means of pre-operative vertebral body embolization - a technique traditionally used to reduce blood loss prior to spinal column tumor resection. We present a 62-year-old man with iatrogenic kyphoscoliosis who underwent staged deformity correction. Stage 1 involved thoracolumbar instrumentation followed by transarterial embolization of the L4 vertebral body through bilateral segmental arteries. A combination of polyvinyl alcohol particles and Gelfoam (Pfizer, New York, NY, USA) were used. Following embolization there was decreased angiographic blood flow to the small vessels of the L4 vertebral body, while the segmental arteries remained patent. Stage 2 consisted of an L4 PSO and fusion. The EBL during the PSO procedure was 1L, which compared favorably to that during previous PSO at this institution as well as to quantities reported in previous literature. There have been no short term (5 month follow-up) complications attributable to the vertebral body embolization or surgical procedure. Although further investigation into this technique is required to better characterize its safety and efficacy in reducing EBL during 3CO, we believe this patient illustrates the potential utility of pre-operative vertebral embolization in the setting of non-oncologic deformity correction surgery.

Balloon-assisted transarterial embolization of type 1 spinal dural arteriovenous fistula.

Type 1 spinal dural arteriovenous fistula (dAVF) constitute the vast majority of all spinal vascular malformations. Here we present the case of a 71-year-old male with progressive myelopathy, lower-extremity weakness and numbness, and urinary incontinence. MRI imaging of the thoracic spine demonstrated cord edema, and catheter spinal angiography confirmed a type 1 spinal dAVF. The fistula was supplied by small dural branches of the left L-2 segmental artery. Angiographic cure was achieved with a one-stage procedure in which coils were used to occlude the distal segmental vessels, followed by balloon-assisted embolization with Onyx. The video can be found here: http://youtu.be/8aehJbueH0U .

Transarterial embolization of an anterior fossa cranial base dural arteriovenous fistula.

Open surgical disconnection has long been the treatment of choice for dural arteriovenous fistulas (dAVFs) of the anterior cranial fossa. However, advanced patient age and the presence of medical comorbidities can substantially increase the risk of craniotomy and favor a less invasive endovascular approach. Optimal positioning within the distal ophthalmic artery, beyond the origin of the central retinal branch, is achievable using current microcatheter technology and embolic materials. Here we present the case of an 88-year-old female with an incidentally discovered dAVF of the anterior cranial fossa. Angiographic cure was achieved with one-stage Onyx embolization. The video can be found here: http://youtu.be/KVE0fUIECQM .

Implications of spinopelvic alignment for the spine surgeon.

The relation of the pelvis to the spine has previously been overlooked as a contributor to sagittal balance. However, it is now recognized that spinopelvic alignment is important to maintain an energy-efficient posture in normal and disease states. The pelvis is characterized by an important anatomic landmark, the pelvic incidence (PI). The PI does not change after adolescence, and it directly influences pelvic alignment, including the parameters of pelvic tilt (PT) and sacral slope (SS) (PI = PT + SS), [corrected] overall sagittal spinal balance, and lumbar lordosis. In the setting of an elevated PI, the spineadapts with increased lumbar lordosis. To prevent or limit sagittal imbalance, the spine may also compensate with increased PT or pelvic retroversion to attempt to maintain anupright posture. Abnormal spinopelvic parameters contribute to multiple spinal conditions including isthmic spondylolysis, degenerative spondylolisthesis, deformity, and impact outcome after spinal fusion. Sagittal balance, pelvic incidence, and all spinopelvic parameters are easily and reliably measured on standing, full-spine (lateral) radiographs, and it is essential to accurately assess and measure these sagittal values to understand their potential role in the disease process, and to promote spinopelvic balance at surgery. In this article, we provide a comprehensive review of the literature regarding the implications of abnormal spinopelvic parameters and discuss surgical strategies for correction of sagittal balance. Additionally, the authors rate and critique the quality of the literature cited in a systematic review approach to give the reader an estimate of the veracity of the conclusions reached from these reports.

Harvey Cushing and "birth hemorrhage": early pediatric neurosurgery at The Johns Hopkins Hospital.

Of Harvey Cushing's many contributions to neurosurgery, one of the least documented is his early surgical intervention in children and his pioneering efforts to establish pediatric neurosurgery as a subspecialty. Between 1896 and 1912 Cushing conducted nearly 200 operations in children at The Johns Hopkins Hospital. A review of his records suggests that the advances he made in neurosurgery were significantly influenced by his experience with children. In this historical article, the authors describe Cushing's treatment of 6 children, in all of whom Cushing established a diagnosis of "birth hemorrhage." By reviewing Cushing's operative indications, techniques, and outcomes, the authors aim to understand the philosophy of his pediatric neurosurgical management and how this informed his development of neurosurgery as a new specialty.

Primary intramedullary spinal germ cell tumors.

BACKGROUND: Intramedullary spinal germ cell tumors are rare lesions, with germinomas being the most common variant. METHODS: To date, there have been 23 reports of primary intramedullary germ cell tumors described in the literature, the vast majority occurring in Japanese patients. RESULTS: We present a case of a nonmetastatic intramedullary germ cell tumor in a 28-year-old Caucasian woman. CONCLUSIONS: Characteristics of intramedullary germ cell tumors are summarized, and the current role for surgery and adjuvant radiation and chemotherapy are discussed.

Impact of tethered cord release on symptoms of Chiari II malformation in children born with a myelomeningocele.

PURPOSE: The role of distal traction in the form of a tethered spinal cord in exacerbating anatomical findings or symptoms of Chiari II malformation (CIIM) has been debated for decades. Despite the association of Chiari II malformation with myelomeningocele, the impact of tethered cord release on CIIM symptoms in patients has not been explored. METHODS: A retrospective review of 59 patients born with a myelomeningocele was performed. A total of 92 untethering procedures were performed in which symptoms of CIIM were present in 29 cases. In 57 out of 92 cases, the patients did not have symptoms of CIIM prior to untethering. Six cases were excluded because cervicomedullary decompression was performed prior to untethering. The response of CIIM symptoms, syrinx size, and cerebellar tonsil position were examined before and after spinal cord untethering. RESULTS: Forty-four characteristic signs and symptoms of CIIM were present prior to 29 untetherings. Thirty-three of 44 (75%) symptoms improved following spinal cord untethering, though no symptom resolved completely. Syrinx size and cerebellar tonsil position were unchanged following untethering. CONCLUSION: The authors conclude that mild to moderate symptoms of CIIM may respond positively to spinal cord untethering, potentially by normalization cerebrospinal fluid flow dynamics. Symptom improvement occurs despite the lack of radiographic evidence of CIIM resolution.

Trans-foraminal versus posterior lumbar interbody fusion: comparison of surgical morbidity.

BACKGROUND: Posterior lumbar interbody fusion (PLIF) and trans-foraminal lumbar interbody fusion (TLIF) are both accepted surgical approaches for spinal fusion in spondylolisthesis and degenerative disc disease. The unilateral approach of TLIF may minimize the risk of iatrogenic durotomy and nerve root injury; however, there is no definitive evidence to support either approach. We review our experience with TLIF versus PLIF to compare operative complications. METHODS: We retrospectively reviewed 119 consecutive cases of PLIF or TLIF performed for degenerative disc disease or spondylolithesis at a single institution over 5 years and examined the incidences of operative complications and outcomes. RESULTS: PLIF was performed in 76 (63%) patients and TLIF in 43 (37%). Patients were 48 ± 13 years old and presented with mechanical back pain [109 (92%)], radicular pain [95 (80%)], and radicular motor weakness [10 (8%)]. Patients undergoing PLIF and TLIF had similar baseline demographic, clinical, and radiographic characteristics. PLIF was associated with a higher incidence of post-operative iatrogenic nerve root dysfunction [6 (7.8%) versus 1 (2%)] and durotomy [13 (17%) versus 4 (9%)]; however, these differences did not reach statistical significance. All cases of nerve root injury were transient and resolved by the third month post-operatively. Estimated operative blood loss, length of hospitalization, and other peri-operative indices were similar between cohorts. By 12 months, evidence of pseudoarthrosis was present in 2 (2.6%) and 2 (4.6%) patients with PLIF or TLIF, respectively. There was a similar incidence of improvement in radicular pain (88% versus 79%) and low back pain (74% versus 80%) between TLIF and PLIF. CONCLUSION: In our experience with surgical management of degenerative disc disease and spondylolesthesis, PLIF versus TLIF was associated with a trend toward a higher incidence of nerve root injury and durotomy. However, iatrogenic nerve root dysfunction was transient in all cases and 12-month pseudoarthrosis rates were similar between cohorts. Similar to previous clinical studies, the incidence of neurological complications and durotomy increases when an interbody fusion is performed through a posterior approach compared to non-interbody fusion techniques. However, the fusion rates with the interbody technique are also enhanced. TLIF and PLIF should only be considered when the goals of surgery cannot be addressed with decompression and traditional posterolateral fusion.

Safety and efficacy of concurrent pediatric spinal cord untethering and deformity correction.

STUDY DESIGN: A retrospective clinical records analysis of concurrent pediatric spinal cord deformity correction and tethered cord release compared with a 2-staged approach. OBJECTIVE: To compare the safety and efficacy of a single-staged approach for pediatric spinal deformity correction and tethered cord release to a conventional 2-staged approach. SUMMARY OF BACKGROUND DATA: Tethered cord syndrome (TCS) is frequently associated with scoliosis in the pediatric population. Conventional practice suggests waiting several months after untethering for scoliosis correction; however, some patients will experience progression of their spinal deformity. We report the efficacy and safety of concurrent tethered cord release and scoliosis and/or kyphosis deformity correction in a series of pediatric patients. METHODS: We retrospectively reviewed 15 consecutive pediatric cases of concurrent spinal cord untethering and deformity correction with fusion for scoliosis and/or kyphosis. The clinical and radiologic presentation, operative details, morbidity, and postoperative outcomes were evaluated. Outcomes of this cohort were then compared with 21 patients who underwent a 2-staged untethering surgery followed by scoliosis correction. We provide a review of the literature of the treatment of tethered cord associated with spine deformities. RESULTS: The mean age of patients undergoing concurrent untethering and curve correction was 9.6 years (5 male, 10 female). Tethered cord was because of myelomeningocele (5 patients), thickened filum terminale (5 patients), lipomyelomeningocele (4 patients), and retethering from an unknown primary TCS etiology (1 patient). The mean scoliosis Cobb angle (±SD) at presentation was 55.4±21.0 degrees (range, 32.3 degrees to 95.0 degrees) whereas average kyphosis was 112.7±43.6 degrees (range, 68.0 degrees to 155.0 degrees). Average postoperative scoliosis curve was 40.0 degrees, resulting in an average correction of 27%; kyphosis curve was 55.7 degrees resulting in an average correction of 50%. The average operation time was 8.6 hours (range, 3.9 to 13.7 h) and the average blood loss was 1266 mL (range, 400 to 5000 mL). Average length of hospitalization was 10.1 days (range, 4 to 34 d). New onset or worsening of neurologic deficits, bowel or bladder dysfunction, or TCS associated pain did not occur in any patients. At a mean follow-up of 5.7 years (range, 1.3 to 11.8 y), only 1 (7%) patient required subsequent surgery for pseudoarthrosis. The 2-staged cohort experienced a longer cumulative operative time (11.2 vs 8.6 h, P<0.05), more total blood loss (1534 vs 1266 mL, P<0.05), longer total days of hospitalization (14.8 vs 10.1 d, P<0.05), and a greater incidence of dural tear (9.5% vs 0%), wound infection (26% vs 0%), and retethering (9.5% vs 0%). CONCLUSION: Concurrent tethered cord release and spinal fusion for correction of scoliosis and/or kyphosis may be a safe and effective approach in patients likely to experience deformity progression.

Sacral tumor resection and the impact on pelvic incidence.

OBJECT: pelvic incidence (PI) directly regulates lumbar lordosis and is a key determinant of sagittal spinal balance in normal and diseased states. Pelvic incidence is defined as the angle between the line perpendicular to the S-1 endplate at its midpoint and the line connecting this point to a line bisecting the center of the femoral heads. It reflects an anatomical value that increases with growth during childhood but remains constant in adulthood. It is not altered by changes in patient position or after traditional lumbosacral spinal surgery. There are only 2 reports of PI being altered in adults, both in cases of sacral fractures resulting in lumbopelvic dissociation and sacroiliac (SI) joint instability. En bloc sacral amputation and sacrectomy are surgical techniques used for resection of certain bony malignancies of the sacrum. High, mid, and low sacral amputations result in preservation of some or the entire SI joint. Total sacrectomy results in complete disruption of the SI joint. The purpose of this study was to determine if PI is altered as a result of total or subtotal sacral resection. METHODS: the authors reviewed a series of 42 consecutive patients treated at The Johns Hopkins Hospital between 2004 and 2009 for sacral tumors with en bloc resection. The authors evaluated immediate pre- and postoperative images for modified pelvic incidence (mPI) using the L-5 inferior endplate, as the patients undergoing a total sacrectomy are missing the S-1 endplate postoperatively. The authors compared the results of total versus subtotal sacrectomies. RESULTS: twenty-two patients had appropriate images to measure pre- and postoperative mPI; 17 patients had high, mid, or low sacral amputations with sparing of some or the entire SI joint, and 5 patients underwent a total sacrectomy, with complete SI disarticulation. The mean change in mPI was statistically different (p < 0.001) for patients undergoing subtotal versus those undergoing total sacrectomy (1.6° ± 0.9° vs 13.6° ± 4.9° [± SD]). There was no difference between patients who underwent a high sacral amputation (partial SI resection, mean 1.6°) and mid or low sacral amputation (SI completely intact, mean 1.6°). CONCLUSIONS: the PI is altered during total sacrectomy due to complete disarticulation of the SI joint and discontinuity of the spine and pelvis, but it is not changed if any of the joint is preserved. Changes in PI influence spinopelvic balance and may have postoperative clinical importance. Thus, the authors encourage attention to spinopelvic alignment during lumbopelvic reconstruction and fixation after tumor resection. Long-term studies are needed to evaluate the impact of the change in PI on sagittal balance, pain, and ambulation after total sacrectomy.

The evolution of surgical management for craniosynostosis.

Craniosynostosis, the premature closure of cranial sutures, has been known to exist for centuries, but modern surgical management has only emerged and evolved over the past 100 years. The success of surgery for this condition has been based on the recognition of scientific principles that dictate brain and cranial growth in early infancy and childhood. The evolution of strip craniectomies and suturectomies to extensive calvarial remodeling and endoscopic suturectomies has been driven by a growing understanding of how a prematurely fused cranial suture can affect the growth and shape of the entire skull. In this review, the authors discuss the early descriptions of craniosynostosis, describe the scientific principles upon which surgical intervention was based, and briefly summarize the eras of surgical management and their evolution to present day.