Challenges in Contemporary Spine Surgery: A Comprehensive Review of Surgical, Technological, and Patient-Specific Issues.

Spine surgery has significantly progressed due to innovations in surgical techniques, technology, and a deeper understanding of spinal pathology. However, numerous challenges persist, complicating successful outcomes. Anatomical intricacies at transitional junctions demand precise surgical expertise to avoid complications. Technical challenges, such as underestimation of the density of fixed vertebrae, individual vertebral characteristics, and the angle of pedicle inclination, pose additional risks during surgery. Patient anatomical variability and prior surgeries add layers of difficulty, often necessitating thorough pre- and intraoperative planning. Technological challenges involve the integration of artificial intelligence (AI) and advanced visualization systems. AI offers predictive capabilities but is limited by the need for large, high-quality datasets and the "black box" nature of machine learning models, which complicates clinical decision making. Visualization technologies like augmented reality and robotic surgery enhance precision but come with operational and cost-related hurdles. Patient-specific challenges include managing postoperative complications such as adjacent segment disease, hardware failure, and neurological deficits. Effective patient outcome measurement is critical, yet existing metrics often fail to capture the full scope of patient experiences. Proper patient selection for procedures is essential to minimize risks and improve outcomes, but criteria can be inconsistent and complex. There is the need for continued technological innovation, improved patient-specific outcome measures, and enhanced surgical education through simulation-based training. Integrating AI in preoperative planning and developing comprehensive databases for spinal pathologies can aid in creating more accurate, generalizable models. A holistic approach that combines technological advancements with personalized patient care and ongoing education is essential for addressing these challenges and improving spine surgery outcomes.

Comparing reactive versus empiric cerebrospinal fluid drainage strategies for spinal perfusion pressure optimization in patients with acute traumatic spinal cord injuries.

BACKGROUND: Spinal cord hypoperfusion undermines clinical recovery in acute traumatic spinal cord injuries. New guidelines suggest cerebrospinal fluid (CSF) drainage is an important strategy for preventing spinal cord hypoperfusion in the acute post-injury phase. METHODS: This study included participants presenting to a single level 1 trauma center between 2018 and 2022 with cervical or thoracic traumatic spinal cord injury severity grade A-C, as evaluated by the American spinal injury association impairment scale (AIS). The primary objective of this study was to compare the efficacy of two CSF drainage protocols in preventing spinal cord hypoperfusion; 1) draining CSF only when spinal cord perfusion pressure (SCPP) drops below 65 mmHg (i.e. reactive) versus 2) empiric CSF drainage of 5-10 mL every hour. Intrathecal pressure, spinal cord perfusion pressure (SCPP), mean arterial pressure (MAP), and vasopressor utilization were compared using univariate T-test statistical analysis. RESULTS: While there was no difference in the incidence of sub-optimal SCPP (<65 mmHg; p = 0.1658), reactively drained participants were more likely to exhibit critical hypoperfusion (<50 mmHg; p = 0.0030) despite also having lower average intrathecal pressures (p < 0.001). There were no differences in average SCPP, mean arterial pressure (MAP), or vasopressor utilization between the two groups (p > 0.05). CONCLUSIONS: Empiric (vs reactive) CSF drainage resulted in fewer incidences of critical spinal cord hypoperfusion for patients with acute traumatic spinal cord injuries.

Evaluating the Need for Durotomy and Duraplasty in Adults Undergoing Suboccipital Craniectomy for Chiari Decompression: A Case Series Analysis of Radiographic and Clinical Outcomes.

Background Suboccipital craniectomy (SOC) in conjunction with dura opening and duraplasty for posterior fossa decompression is an effective treatment for symptomatic Chiari 1 malformations (CM1), primarily carried out in the pediatric population. However, dural opening and reconstruction are associated with an increased risk of complications, and their necessity in the adult population has not yet been robustly demonstrated. Given differences in clinical presentation and disease severity between the pediatric and adult patients, we aimed to identify if SOC alone with intraoperative ultrasound confirmation of adequate restoration of pulsatile motion of cerebellar tonsil is sufficient to treat symptomatic CM1 while mitigating surgical risks. Methods We identified a retrospective, institutional cohort of adult patients who underwent SOC for Chiari decompression between 2014 and 2023. Demographic, clinical, and radiographic features were extracted for each patient. Clinical outcomes were assessed using the Chicago Chiari Outcome Scale (CCOS) and Motor-Sensory-Sphincter signs score (Clinical Sign Score (CSS)). Radiographic outcomes assessed cerebellar ectopia and associated syrinx characteristics. Results A total of 15 patients were identified, with an average follow-up period of three years. Eight patients underwent SOC with duraplasty, whereas seven patients underwent SOC only without duraplasty. Both groups of patients were of similar age at surgery and had similar nature and duration of symptoms prior to surgery. On pre-operative radiographic evaluation, both groups of patients had similar lengths of cerebellar ectopia (9.9±11.0 mm to 11.1±5.7 mm, p=0.591), and associated syrinxes (75% vs. 42.9%, p=0.205). Intraoperatively, both groups had similar estimated blood losses, though the length of surgery was significantly shorter when durotomy was spared (202±58.3 minutes to 116.3±47.8 minutes, p=0.011). The length of ICU stay was also significantly longer in the durotomy group (1.1±0.6 days to 0.0 days, p<0.001). Neither group reported any post-operative complications. On follow-up, both groups demonstrated similar reductions in cerebellar ectopia and syrinx characteristics. Clinically, the CCOS and CSS scores were similar between the two cohorts at follow-up, with no repeat surgery required in either group. Conclusion Our cohort suggests that for adult CM1 patients, SOC decompression alone without dural reconstruction might lead to comparable clinical and radiographic outcomes to SOC decompression with durotomy/duraplasty, especially if intraoperative ultrasound confirms good cerebrospinal fluid (CSF) flow after SOC. Notably, sparing durotomy and duraplasty is also associated with decreased operative time and decreased ICU stay.

Benign Natural Progression of Small Cavernous Carotid Aneurysms Suggests Limited Clinical Utility of Serial Longitudinal Follow-up.

BACKGROUND AND OBJECTIVES: Aneurysms in the cavernous segment of the internal carotid artery (ICA) often present in an indolent fashion with limited morbidity. However, their growth progression and possible rupture over time remains poorly defined, thereby limiting optimization of serial follow-up. Thus, we aim to describe the progression of cavernous ICA aneurysms over time, as well as the patient and aneurysm characteristics associated with possible growth and rupture status. METHODS: We identified a consecutive cohort of 157 patients from 2007 to 2021 with cavernous ICA aneurysms. Patient demographic data, possible risk factors, presenting symptoms, radiographic features of aneurysms, size progression, rupture status, and concomitant noncavernous aneurysm rupture data were manually extracted. RESULTS: One hundred and fifty-seven patients (mean age at diagnosis 57.2 ± 15.6 years; 85.4% females) with 174 cavernous carotid aneurysms (CCAs) were followed for an average of 7.1 ± 4.8 years. 76.4% of aneurysms were identified incidentally, with predominantly ocular palsies as the presenting symptoms in remaining primary cases. Most aneurysms were small, and of the 168 aneurysms that were followed, 98.2% did not demonstrate appreciable growth. Of the aneurysms that grew, it took an average of 6.0 years to grow 1.6 ± 0.2 mm. Demographic data, hypertension, and smoking status were not associated with aneurysm growth. Most radiographic features also were not associated with growth, except long-axis diameter, which had an odds ratio of 1.4 (CI: 1.2, 1.8) on multivariable analysis. Presenting clinical symptoms were not associated with growth. No CCAs ruptured during follow-up. CONCLUSION: Cavernous ICA aneurysms in our series demonstrate no rupture and limited growth over years of clinical follow-up. No radiographic or patient risk factors were associated with growth except initial aneurysm size. Hence, small CCAs may not require close follow-up over time.

Advances and Evolving Challenges in Spinal Deformity Surgery.

BACKGROUND: Surgical intervention is a critical tool to address adult spinal deformity (ASD). Given the evolution of spinal surgical techniques, we sought to characterize developments in ASD correction and barriers impacting clinical outcomes. METHODS: We conducted a literature review utilizing PubMed, Embase, Web of Science, and Google Scholar to examine advances in ASD surgical correction and ongoing challenges from patient and clinician perspectives. ASD procedures were examined across pre-, intra-, and post-operative phases. RESULTS: Several factors influence the effectiveness of ASD correction. Standardized radiographic parameters and three-dimensional modeling have been used to guide operative planning. Complex minimally invasive procedures, targeted corrections, and staged procedures can tailor surgical approaches while minimizing operative time. Further, improvements in osteotomy technique, intraoperative navigation, and enhanced hardware have increased patient safety. However, challenges remain. Variability in patient selection and deformity undercorrection have resulted in heterogenous clinical responses. Surgical complications, including blood loss, infection, hardware failure, proximal junction kyphosis/failure, and pseudarthroses, pose barriers. Although minimally invasive approaches are being utilized more often, clinical validation is needed. CONCLUSIONS: The growing prevalence of ASD requires surgical solutions that can lead to sustained symptom resolution. Leveraging computational and imaging advances will be necessary as we seek to provide comprehensive treatment plans for patients.

Metastatic pituitary tumors: an institutional case series.

PURPOSE: Pituitary carcinomas are a rare entity that respond poorly to multimodal therapy. Patients follow a variable disease course that remains ill-defined. METHODS: We present an institutional case series of patients treated for pituitary carcinomas over a 30-year period from 1992 to 2022. A systematic review was conducted to identify prior case series of patients with pituitary carcinomas. RESULTS: Fourteen patients with a mean age at pituitary carcinoma diagnosis of 52.5 years (standard deviation [SD] 19.4) met inclusion criteria. All 14 patients had tumor subtypes confirmed by immunohistochemistry and hormone testing, with the most common being ACTH-producing pituitary adenomas (n = 12). Patients had a median progression-free survival (PFS) of 1.4 years (range 0.7-10.0) and a median overall survival (OS) of 8.4 years (range 2.3-24.0) from pituitary adenoma diagnosis. Median PFS and OS were 0.6 years (range 0.0-2.2) and 1.5 years (range 0.1-9.6) respectively upon development of metastases. Most patients (n = 12) had locally invasive disease to the cavernous sinus, dorsum sellae dura, or sphenoid sinus prior to metastasis. Common sites of metastasis included the central nervous system, liver, lung, and bone. In a pooled analysis including additional cases from the literature, treatment of metastases with chemotherapy or a combination of radiation therapy and chemotherapy significantly prolonged PFS (p = 0.02), while failing to significantly improve OS (p = 0.14). CONCLUSION: Pituitary carcinomas are highly recurrent, heterogenous tumors with variable responses to treatment. Multidisciplinary management with an experienced neuro-endocrine and neuro-oncology team is needed given the unrelenting nature of this disease.

Utility of Expandable Interbody Cages in Open Transforaminal Interbody Fusions: A Comparison With Static Cages.

Background Expandable interbody cages, while popular in minimally invasive fusions due to their slim profile and increased ease of insertion, have not been widely explored in open surgery. The benefits of expandable cages may also extend to open fusions through their potential to achieve a greater restoration of lumbar lordosis while minimizing intraoperative complications. To highlight these benefits, we present a case series of adult spinal deformity (ASD) patients treated with an open transforaminal lumbar interbody fusion (TLIF) using expandable cages and compare outcomes to those of patients treated with static cages from the literature. Methods A retrospective cohort study of patients who underwent a deformity correction procedure and TLIF with expandable interbody cages at Brigham and Women's Hospital between 2018 and 2022 was conducted. Patient demographics, complications, and pre- and postoperative radiographic parameters of spinopelvic alignment were collected. A literature search was completed to identify studies employing static cages. T-tests were performed to compare postoperative changes in radiographic parameters by cage type. Results Forty-five patients (mean age of 62.6 years) with an average of 2.1 cages placed met the inclusion criteria. Patients experienced five intraoperative complications and 23 neurologic deficits (from minor to major), while nine patients required a revision operation. Lumbar lordosis increased by 9.8° ± 14.5° (p < 0.0001), the sagittal vertical axis (SVA) decreased by 25.5 mm ± 56.7 mm (p = 0.0048), and pelvic incidence-lumbar lordosis mismatch decreased by 13.3° ± 17.5° (p < 0.0001) with the use of expandable cages. Expandable cages yielded similar changes in lumbar lordosis to 15° and 8° cages but improved the lumbar lordosis generated from rectangular and 4° cages. When compared to static cages, expandable cages mildly reduced intraoperative complications. Conclusions Expandable interbody cages are an effective means of restoring spinopelvic alignment in ASD that have the potential to improve patient outcomes in open fusions compared to standard static cages. Especially when compared to rectangular and 4° static cages, expandable cages provide a clear benefit in the correction of lumbar lordosis. The impact of open spinal fusions with expandable cages on outcomes should continue to be explored in other cohorts.

Spinal Metastases from Colorectal Cancer at Mass General Brigham: A Twenty-Year Case Series With Literature Review.

OBJECTIVE: We present an institutional case series of patients treated for colorectal carcinoma (CRC) spinal metastases to investigate the outcomes between no treatment, radiation, surgery, and surgery/radiation. METHODS: A retrospective cohort of patients with CRC spinal metastases presenting to affiliated institutions between 2001 and 2021 wereidentified. Information related to patient demographics, treatment modality, treatment outcomes, symptom improvement, and survival was collected by chart review. Overall survival (OS) was compared between treatments by log-rank significance testing. A literature review was conducted to identify other cases series of CRC patients with spinal metastases. RESULTS: Eighty-nine patients (mean age 58.5) with CRC spinal metastases across a mean of 3.3 levels met inclusion criteria: 14 (15.7%) received no treatment, 11 (12.4%) received surgery alone, 37 (41.6%) received radiation alone, and 27 (30.3%) received both radiation and surgery. Patients treated with combination therapy had the longest median OS of 24.7 months (range 0.6-85.9), which did not significantly differ from the median OS of 8.9 months (range 0.2-42.6) observed in patients who received no treatment (P = 0.075). Combination therapy provided objectively longer survival time in comparison to other treatment modalities but failed to reach statistical significance. The majority of patients that received treatment (n = 51/75, 68.0%) experienced some degree of symptomatic or functional improvement. CONCLUSIONS: Therapeutic intervention has the potential to improve the quality of life in patients with CRC spinal metastases. We demonstrate that surgery and radiation are useful options for these patients, despite their lack of objective improvement in OS.

Treating the dead; how far ought medicine go to obtain transplantable organs?

Under what circumstances, is it ethical to perform tumor surgery on a brain-dead individual? The neurosurgeons at Brigham and Women's Hospital were recently faced with such a question when asked to operate on a 28-year-old man who was pronounced brain-dead secondary to a severe brain-stem injury. His advanced directives clearly documented a desire for organ donation. During his transplant work-up, cranial imaging suggested a possible cerebellar mass of unknown etiology that was concerning for metastatic disease. Despite negative full body imaging, the neurosurgical team was asked to perform an open biopsy of the intracranial lesion to rule out occult systemic cancer. This case invites many nuanced questions related to the decisions surgeons and the broader medical community must make in the face of pursuing viable organs for the many in need. What is the moral standing and personhood eligibility of brain-dead individuals? What is the scope of medical interventions and procedures that surgeons are ethically bound to carry out? How ought the desire for increased medical intervention to try to save organs be balanced with practical limitations given limited medical resources?

The Relationship Among Surgeon Experience, Complications, and Radiographic Outcomes in Spine Deformity Surgery: The Experience of a Junior Surgeon.

OBJECTIVE: To examine complication rates and radiographic outcomes in patients undergoing surgery for adult spinal deformity (ASD) by a junior surgeon. METHODS: A study was conducted of a retrospective cohort of patients who underwent an open posterior interbody fusion of the thoracic and/or lumbar regions by a single surgeon for ASD between 2018 and 2022. Patient characteristics, complications, and common radiographic parameters of spinopelvic alignment were collated. RESULTS: A total of 112 patients with an average of 4.2 comorbidities underwent surgical correction of ASD. Thirty-seven patients (33.0%) experienced 52 major complications and 50 patients (44.6%) experienced 66 minor complications. Twenty-three patients (20.5%) required a revision operation. Both sagittal vertical axis (P < 10-14) and pelvic incidence-lumbar lordosis mismatch (P < 10-7) significantly improved postoperatively. Number of levels (P < 0.05), operative time >650 minutes (P < 0.01), estimated blood loss >1500 mL (P < 0.01), length of intensive care unit stay >1 day (P < 0.05), and hospitalization length >5 days (P < 0.05) all significantly increased the risk of a major complication. No patient factors significantly increased the risk of minor complications or revision surgery. CONCLUSIONS: Observed complication and revision rates in this cohort were consistent with rates reported in the literature. No preoperative patient risk factors significantly increased risk of complications or need for revision, suggesting that no patient population is at increased risk undergoing surgery by a junior surgeon. The relatively high rate of complications observed in this cohort may be a result of high baseline morbidity.

Subtype Diversification and Synaptic Specificity of Stem Cell-Derived Spinal Interneurons.

Neuronal diversification is a fundamental step in the construction of functional neural circuits, but how neurons generated from single progenitor domains acquire diverse subtype identities remains poorly understood. Here we developed an embryonic stem cell (ESC)-based system to model subtype diversification of V1 interneurons, a class of spinal neurons comprising four clades collectively containing dozens of molecularly distinct neuronal subtypes. We demonstrate that V1 subtype diversity can be modified by extrinsic signals. Inhibition of Notch and activation of retinoid signaling results in a switch to MafA clade identity and enriches differentiation of Renshaw cells, a specialized MafA subtype that mediates recurrent inhibition of spinal motor neurons. We show that Renshaw cells are intrinsically programmed to migrate to species-specific laminae upon transplantation and to form subtype-specific synapses with motor neurons. Our results demonstrate that stem cell-derived neuronal subtypes can be used to investigate mechanisms underlying neuronal subtype specification and circuit assembly.

Converging Mechanisms of p53 Activation Drive Motor Neuron Degeneration in Spinal Muscular Atrophy.

The hallmark of spinal muscular atrophy (SMA), an inherited disease caused by ubiquitous deficiency in the SMN protein, is the selective degeneration of subsets of spinal motor neurons. Here, we show that cell-autonomous activation of p53 occurs in vulnerable but not resistant motor neurons of SMA mice at pre-symptomatic stages. Moreover, pharmacological or genetic inhibition of p53 prevents motor neuron death, demonstrating that induction of p53 signaling drives neurodegeneration. At late disease stages, however, nuclear accumulation of p53 extends to resistant motor neurons and spinal interneurons but is not associated with cell death. Importantly, we identify phosphorylation of serine 18 as a specific post-translational modification of p53 that exclusively marks vulnerable SMA motor neurons and provide evidence that amino-terminal phosphorylation of p53 is required for the neurodegenerative process. Our findings indicate that distinct events induced by SMN deficiency converge on p53 to trigger selective death of vulnerable SMA motor neurons.