Medical and surgical management of pneumothorax in diving and hyperbaric chambers.

The presence of a pneumothorax within a pressurized chamber represents unique diagnostic and management challenges. This is particularly the case in the medical and geographic remoteness of many chamber locations. Upon commencing chamber decompression, unvented intrapleural air expands. If its initial volume and/or degree of chamber pressure reduction is significant enough, a tension pneumothorax will result. Numerous reports chronicle failure to diagnose and manage in-chamber pneumothorax with resultant morbidity and one fatal outcome. Such cases have occurred in both medically remote and clinically based settings. This paper reviews pneumothorax and tension pneumothorax risk factors and clinical characteristics. It suggests primary medical management using the principle of oxygen-induced inherent unsaturation in concert with titrated chamber decompression designed to prevent intrapleural air expanding faster than it contracts. Should this conservative approach prove unsuccessful, and surgical venting becomes necessary or otherwise immediately indicated, interventional options are reviewed.

Pneumothorax during manned chamber operations: A summary of reported cases.

In-chamber pneumothorax has complicated medically remote professional diving operations, submarine escape training, management of decompression illness, and hospital-based provision of hyperbaric oxygen therapy. Attempts to avoid thoracotomy by combination of high oxygen partial pressure breathing (the concept of inherent unsaturation) and greatly slowed rates of chamber decompression proved successful on several occasions. When this delicate balance designed to prevent the intrapleural gas volume from expanding faster than it contracts proved futile, chest drains were inserted. The presence of pneumothorax was misdiagnosed or missed altogether with disturbing frequency, resulting in wide-ranging clinical consequences. One patient succumbed before the chamber had been fully decompressed. Another was able to ambulate unaided from the chamber before being diagnosed and managed conventionally. In between these two extremes, patients experienced varying degrees of clinical compromise, from respiratory distress to cardiopulmonary arrest, with successful resuscitation. Pneumothorax associated with manned chamber operations is commonly considered to develop while the patient is under pressure and manifests during ascent. However, published reports suggest that many were pre-existing prior to chamber entry. Risk factors included pulmonary barotrauma-induced cerebral arterial gas embolism, cardiopulmonary resuscitation, and medical or surgical procedures usually involving the lung. This latter category is of heightened importance to hyperbaric operations as an iatrogenically induced pneumothorax may take as long as 24 hours to be detected, perhaps long after a patient has been cleared for chamber exposure.

Decompression sickness followed by diabetic ketoacidosis and sepsis shock: an unusual case report.

Decompression sickness (DCS) is caused by abrupt changes in extracorporeal pressure with varying severity. Symptoms range from mild musculoskeletal pain to severe organ dysfunction and death, especially among patients with chronic underlying disease. Here, we report an unusual case of a 49-year-old man who experienced DCS after a dive to a depth of 38 meters. The patient's symptoms progressed, starting with mild physical discomfort that progressed to disturbance of consciousness on the second morning. During hospitalization, we identified that in addition to DCS, he had also developed diabetic ketoacidosis, septic shock, and rhabdomyolysis. After carefully balancing the benefits and risks, we decided to provide supportive treatment to sustain vital signs, including ventilation support, sugar-reducing therapy, fluid replacement, and anti-infection medications. We then administered delayed hyperbaric oxygen (HBO2) when his condition was stable. Ultimately, the patient recovered without any sequelae. This is the first case report of a diver suffering from DCS followed by diabetic ketoacidosis and septic shock. We have learned that when DCS and other critical illnesses are highly suspected, it is essential to assess the condition comprehensively and focus on the principal contradiction.

In-field use of I-VED electrical impedance sensor for assessing post-dive decompression stress in humans.

Purpose: Ultrasound imaging is commonly used in decompression research to assess venous gas emboli (VGE) post-dive, with higher loads associated with increased decompression sickness risk. This work examines, for the first time in humans, the performance of a novel electrical impedance spectroscopy technology (I-VED), on possible detection of post-dive bubbles presence and arterial endothelial dysfunction that may be used as markers of decompression stress. Methods: I-VED signals were recorded in scuba divers who performed standardized pool dives before and at set time points after their dives at 35-minute intervals for about two hours. Two distinct frequency components of the obtained signals, Low-Pass Frequency-LPF: 0-0.5 Hz and Band-Pass Frequency-BPF: 0.5-10 Hz, are extracted and respectively compared to VGE presence and known flow-mediated dilation trends for the same dive profile for endothelial dysfunction. Results: Subjects with VGE counts above the median for all subjects were found to have an elevated average LPF compared to subjects with lower VGE counts, although this was not statistically significant (p=0.06), as well as significantly decreased BPF standard deviation post-dive compared to pre-dive (p=0.008). Conclusions: I-VED was used for the first time in humans and operated to provide qualitative in-vivo electrical impedance measurements that may contribute to the assessment of decompression stress. Compared to ultrasound imaging, the proposed method is less expensive, not operator-dependent and compatible with continuous monitoring and application of multiple probes. This study provided preliminary insights; further calibration and validation are necessary to determine I-VED sensitivity and specificity.

Navigation-guided endoscopic lumbar decompression on foramen and lateral recess in advanced scoliosis.

An 84-year-old woman presented with left leg radiating pain for 18 months and a numeric rating scale score of 8. From examination, motoric on left knee extension was grade 4, with dysesthesia and numbness along the left anterolateral thigh. Imaging showed left L3-4 foraminal and lateral recess stenosis with severe-degree scoliosis. The patient underwent navigation-guided endoscopic transforaminal foraminotomy and lateral recess decompression on the left L3-4 level with a good outcome. Three-years' follow-up showed a well-maintained clinical outcome and coronal sagittal balance. This video explores navigation-guided endoscopic lumbar decompression for neural compression in advanced scoliosis. Further research is encouraged to establish long-term efficacy. The video can be found here: https://stream.cadmore.media/r10.3171/2024.1.FOCVID23195.

Five-step unilateral biportal endoscopic surgery for central lumbar canal stenosis: "Z" technique nuance.

The treatment for lumbar spinal stenosis has advanced through the use of minimally invasive surgery techniques. Endoscopic methods go even further, with studies showing that both uniportal and biportal endoscopic techniques have outcomes comparable to traditional approaches. However, there is limited knowledge of the step-by-step decompression process when using the unilateral biportal endoscopic (UBE). To address this, the authors introduce the five steps in the "Z" sequence, which aims to reduce surgical time and complications. The video can be found here: https://stream.cadmore.media/r10.3171/2024.1.FOCVID23182.

Clinical observation of 10-mm endoscopic minimally invasive interlaminar decompression in the treatment of ossified lumbar spinal stenosis.

PURPOSE: This study aims to observe the safety and effectiveness of 10-mm endoscopic minimally invasive interlaminar decompression in the treatment of ossified lumbar spinal stenosis. METHODS: The clinical data of 50 consecutive patients with ossified lumbar spinal stenosis were retrospectively analyzed. All patients underwent minimally invasive interlaminar decompression with 10-mm endoscope. Patient demographics, perioperative data, and clinical outcomes were recorded. Visual analog scale (VAS) scores, Oswestry disability index (ODI) scores, and modified Macnab criteria were used to assess clinical outcomes. The lateral recess angle, real spinal canal area and effective intervertebral foramen area were used to assess the effect of decompression. RESULTS: The mean age of all patients was 59.0±12.3 years. The mean operative time and intraoperative blood loss were 43.7±8.7 minutes and <20ml, respectively. Two years after surgery, the leg pain VAS score decreased from 7.4 ± 1.0 to 1.6 ± 0.6 (P < 0.05) and the ODI score decreased from 63.8 ± 7.6 to 21.7 ± 3.4 (P < 0.05). The lateral recess angle, real spinal canal area and effective intervertebral foramen area were significantly larger than before surgery (P < 0.05). The overall excellent and good rate at the last follow-up was 92.0% according to the modified Macnab criteria. CONCLUSION: The 10-mm endoscopic minimally invasive interlaminar decompression can safely and effectively remove the ossification in the spinal canal and achieve adequate decompression in patients with ossified lumbar spinal stenosis.

Safety and efficacy of endoscope-assisted versus microscopic microvascular decompression surgery for hemifacial spasm: a prospective cohort study.

Microscopic microvascular decompression (M-MVD) is a classical treatment for relieving long-term hemifacial spasms (HFS). An endoscopy technique has recently been introduced to improve M-MVD; however, this application remains debatable. This study compared the safety and effectiveness of endoscope-assisted microvascular decompression (EA-MVD) and M-MVD for HFS. From February 2021 to September 2022, we enrolled 49 patients with HFS assigned to the EA-MVD (n = 26) and M-MVD (n = 23) groups. The patients were assessed with Park YS grades, operative time, hospital days, and complications. Evaluations were performed in the early postoperative period, at one month, 3 months, 6 months, and at least 12 months. Twenty-three (23/26, 88.5%) patients in the EA-MVD group and 20 (20/23, 87.0%) patients in the M-MVD group achieved spasm-free relief, ranging over "excellent" and "good" Park YS grades. The operative time in the EA-MVD and M-MVD groups were 143 ± 28 min and 145 ± 22 min (p = 0.002). The duration of hospital stay was 6.8 ± 0.8 days and 7.2 ± 1.3 days in the EA-MVD and M-MVD groups (p = 0.002), respectively. All surgeries for HFS were successful, with no death, stroke, hearing loss, facial numbness, or other extreme complications. In conclusion, EA-MVD, compared with M-MVD, demonstrated equally effective outcomes with decreased operative time and hospital stays, providing bright intraoperative illumination and flexible surgical vision.

Timing of decompression in central cord syndrome: a systematic review and meta-analysis.

PURPOSE: This study compared the recovery of motor function and the safety of early and delayed surgical intervention in patients with central cord syndrome (CCS). METHODS: PubMed, Embase, Cochrane Library, and Web of Science were employed to retrieve the targeted studies published from inception to February 19, 2023. Comparative studies of early versus delayed surgical decompression in CCS based on American Spinal Injury Association motor score (AMS) recovery, complication rates, and mortality were selected. The statistical analyses were performed using STATA 16.0 and RevMan 5.4. RESULTS: Our meta-analysis included 13 studies comprising 8424 patients. Results revealed that early surgery improved AMS scores significantly compared with delayed surgery, with an increase in MDs by 7.22 points (95% CI 1.98-12.45; P = 0.007). Additionally, early surgery reduced the complication rates than delayed surgery (OR 0.53, 95% CI 0.42-0.67, P < 0.00001). However, no significant difference was observed in mortality between the two groups (OR 0.97; 95% CI 0.75-1.26; P = 0.84). CONCLUSIONS: Early surgical decompression for CCS can improve motor function and reduce the incidence of complications without affecting the mortality rate in patients. Future research should focus on investigating and analyzing the optimal window period for early CCS surgery. Additionally, the timing of surgery should be determined based on the patient's condition and available medical resources.

Chronic Subdural Hematoma in a Middle-Aged Amateur Scuba Diver: A Case Report.

Scuba diving has become a common and popular activity, and adverse events can occur following this activity. Among those events, intracranial hemorrhage is very rare, and only intracerebral hemorrhage and subarachnoid hemorrhage are reported. However, the occurrence of chronic subdural hematoma (CSDH), possibly as an adverse event following scuba diving, has not been described. A 49-year-old man with no significant medical history visited our hospital complaining of memory disturbance and aphasia. He had experienced a minor head trauma five months before and had gone scuba diving six times between the traumatic episode and the visit to our hospital. A brain computed tomography scan revealed a left CSDH. The patient underwent burr-hole surgery to remove the CSDH, and his symptoms resolved. We report the first case of CSDH possibly related to scuba diving. No recurrence of CSDH was observed at 28 months postoperatively.

Machine learning for enhanced prognostication: predicting 30-day outcomes following posterior fossa decompression surgery for Chiari malformation type I in a pediatric cohort.

OBJECTIVE: Chiari malformation type I (CM-I) is a congenital disorder occurring in 0.1% of the population. In symptomatic cases, surgery with posterior fossa decompression (PFD) is the treatment of choice. Surgery is, however, associated with peri- and postoperative complications that may require readmission or renewed surgical intervention. Given the associated financial costs and the impact on patients' well-being, there is a need for predictive tools that can assess the likelihood of such adverse events. The aim of this study was therefore to leverage machine learning algorithms to develop a predictive model for 30-day readmissions and reoperations after PFD in pediatric patients with CM-I. METHODS: This was a retrospective study based on data from the National Surgical Quality Improvement Program-Pediatric database. Eligible patients were those undergoing PFD (Current Procedural Terminology code 61343) for CM-I between 2012 and 2021. Patients undergoing surgery for tumors or vascular lesions were excluded. Unplanned 30-day readmission and unplanned 30-day reoperation were the main study outcomes. Additional outcome data considered included the length of hospital stay, 30-day complications, discharge disposition, and 30-day mortality. Training and testing samples were randomly generated (80:20) to study the 30-day readmission and reoperation using logistic regression, decision tree, random forest (RF), K-nearest neighbors, and Gaussian naive Bayes algorithms. RESULTS: A total of 7106 pediatric patients undergoing PFD were included. The median age was 9.2 years (IQR 4.7, 14.2 years). Most of the patients were female (56%). The 30-day readmission and reoperation rates were 7.5% and 3.4%, respectively. Headaches (32%) and wound-related complications (30%) were the most common reasons for 30-day readmission, while wound revisions and evacuation of fluid or blood (62%), followed by CSF diversion-related procedures (28%), were the most common reasons for 30-day reoperation. RF classifiers had the highest predictive accuracy for both 30-day readmissions (area under the curve [AUC] 0.960) and reoperations (AUC 0.990) compared with the other models. On feature importance analysis, sex, developmental delay, ethnicity, respiratory disease, premature birth, hydrocephalus, and congenital/genetic anomaly were some of the variables contributing the most to both RF models. CONCLUSIONS: Using a large-scale nationwide dataset, machine learning models for the prediction of both 30-day readmissions and reoperations were developed and achieved high accuracy. This highlights the utility of machine learning in risk stratification and surgical decision-making for pediatric CM-I.

Long-term outcome of microvascular decompression for typical trigeminal neuralgia with autologous muscle: an analysis of 1025 patients from a developing country.

OBJECTIVE: The objective was to evaluate the long-term outcome of microvascular decompression (MVD) utilizing autologous muscle for trigeminal neuralgia (TGN). METHODS: A retrospective review was performed of all first-time MVD patients for typical classic TGN without prior surgical intervention who were treated between 2000 and 2019 at a tertiary supraregional neurosurgery practice. Demographic characteristics, surgical findings, operative results, complications, and recurrence rates at 1 year, 5 years, and last follow-up were collected. Pain outcome was assessed using the Barrow Neurological Institute (BNI) pain score. The chi-square test with continuity correction was used to compare categorical variables, and Kaplan-Meier curves and Cox regression were used to identify factors associated with recurrence. RESULTS: In total, 1025 patients were studied with a median (interquartile range [IQR]) (range) follow-up of 8 (5-13) (3-20) years. In the immediate postoperative period, 889 patients (86.7%) had complete pain relief and 106 (10.3%) had partial pain relief; neither group required medication, and 30 patients (2.9%) had no relief. One hundred forty-one recurrences (13.8%) occurred over a median (IQR) of 3 (2-6) years after surgery. The proportion of patients without recurrence was 97% at 1 year, 90% at 5 years, 85% at 10 years, 82% at 15 years, and 81% at 20 years. There was no significant difference in the probability of recurrence between patients with complete (114/907 [12.6%] recurrences) or partial (19/106 [17.9%] recurrences) postoperative pain relief (p = 0.124, log-rank test). Patients with venous compression (n = 322) had a significantly higher rate of MVD failure (n = 16 [5%]) compared to those with arterial compression (14/703 [2%]) (p = 0.015, chi-square test). In the Cox proportional hazards model, venous compression and lack of immediate postoperative pain relief had hazard ratios of 1.62 (95% CI 1.16-2.27) and 2.65 (95% CI 1.45-4.82) for recurrence, respectively. One hundred twenty-four (12.1%) complications were documented, including facial numbness (44 [4.3%]), facial nerve palsy (37 [3.6%]), CSF leak (13 [1.3%]), and diplopia (5 [0.5%]), which resolved in all patients. CONCLUSIONS: MVD with autologous muscle provides long-lasting pain relief in TGN patients with vascular compression with minimum morbidity and is a viable alternative to synthetic materials.

Balanced medial-lateral wall vs selective 3-wall orbital decompression for sight-threatening Graves's orbitopathy: a clinical retrospective cohort study from 2016 to 2022.

PURPOSE: Although urgent orbital decompression surgery for sight-threatening Graves' orbitopathy unresponsive to available medical treatments continues to evolve, post-operative new-onset or worsened pre-operative strabismus or diplopia remains a significant complication. At present, the optimal surgical technique remains debatable. Here, we sought to compare long-term outcomes after balanced medial-lateral wall versus selective 3-wall decompression as an urgent treatment for unresponsive sight-threatening GO. METHODS: This retrospective study examined the post-operative outcome of 102 eyes (57 patients) that underwent urgent orbital decompression for sight-threatening GO. Treatment effectiveness was measured by visual acuity, proptosis, perimetry, and strabismus/diplopia, while fundus findings were detected by fundus color photography and optical coherence tomography and followed up for more than 12 months. RESULTS: Fifty-seven patients (102 orbits) with an average age of 52.7 ± 10.2 years were evaluated. Balanced medial-lateral wall (BMLW-OD) or selective 3-wall decompression(S3W-OD) were performed in 54 and 48 eyes, respectively. Twelve months after orbital decompression, all parameters significantly improved in both groups, including best-corrected visual acuity (BCVA), mean defect of visual field (VF-MD), pattern standard deviation of visual field (VF-PSD), and proptosis (all P < 0.01). However, new-onset esotropia occurred in 25.8% and 3.8% of patients who underwent BMLW-OD surgery or S3W-OD, respectively. Moreover, 6.5% and 38.5% of patients improved after decompression in the medial-lateral wall decompression group and the selective 3-wall decompression group, respectively. CONCLUSIONS: We demonstrated that S3W-OD provides a lower rate of new-onset strabismus/diplopia as compared with BMLW-OD surgery, while still allowing for satisfactory visual outcomes. TRIAL REGISTRATION NUMBER:  : NCT05627401. Date of registration: November 25, 2022.

Evolution of Cervical Endoscopic Spine Surgery: Current Progress and Future Directions-A Narrative Review.

Cervical endoscopic spine surgery is rapidly evolving and gaining popularity for the treatment of cervical radiculopathy and myelopathy. This approach significantly reduces muscular damage and blood loss by minimizing soft tissue stripping, leading to less postoperative pain and a faster postoperative recovery. As scientific evidence accumulates, the efficacy and safety of cervical endoscopic spine surgery are continually affirmed. Both anterior and posterior endoscopic approaches have surfaced as viable alternative treatments for various cervical spine pathologies. Newer techniques, such as endoscopic-assisted fusion, the anterior transcorporeal approach, and unilateral laminotomy for bilateral decompression, have been developed to enhance clinical outcomes and broaden surgical indications. Despite its advantages, this approach faces challenges, including a steep learning curve, increased radiation exposure for both surgeons and patients, and a relative limitation in addressing multi-level pathologies. However, the future of cervical endoscopic spine surgery is promising, with potential enhancements in clinical outcomes and safety on the horizon. This progress is fueled by integrating advanced imaging and navigation technologies, applying regional anesthesia for improved and facilitated postoperative recovery, and incorporating cutting-edge technologies, such as augmented reality. With these advancements, cervical endoscopic spine surgery is poised to broaden its scope in treating cervical spine pathologies while maintaining the benefits of minimized tissue damage and rapid recovery.

Clinical efficacy and imaging analysis of oblique lateral lumbar interbody fusion in the treatment of different types of lumbar intervertebral foramen stenosis.

PURPOSE: To analyze and study the clinical efficacy and imaging indexes of oblique lateral lumbar interbody fusion (OLIF) in the treatment of lumbar intervertebral foramen stenosis(LFS) caused by different causes. METHOD: 33 patients with LFS treated with OLIF from January 2018 to May 2022 were reviewed. Oswestry Dysfunction Index (ODI) and visual analogue scale (VAS) were calculated before and after operation. Segmental lordotic angle (SLA), lumbar lordotic angle (LLA) and segmental scoliosis angle (SSA), disc height (DH), posterior disc height (PDH), lateral disc height (LDH), foraminal height (FH), foramen width (FW) and foraminal cross-sectional area (FSCA) were measured before and after operation. RESULT: The VAS and ODI after operation were significantly improved as compared with those before operation. Compared with pre-operation, the DH, PHD increased by 67.6%, 94.6%, LDH increased by 107.4% (left), 101.7% (right), and FH increased by 30.2% (left), 34.5% (right). The FSCA increased by 93.1% (left), 89.0% (right), and the FW increased by 137.0% (left), 149.6% (right). The postoperative SSA was corrected by 74.5%, the postoperative SLA, LLA were corrected by 70.2%, 38.1%, respectively. All the imaging indexes were significantly improved (p < 0.01). CONCLUSION: The clinical efficacy and imaging data of OLIF in the treatment of LFS caused by low and moderate lumbar spondylolisthesis, intervertebral disc bulge and reduced intervertebral space height, degenerative lumbar scoliosis, articular process hyperplasia or dislocation have been well improved. OLIF may be one of the better surgical treatments for LFS caused by the above conditions.

Radiologic Evaluation of Uncinate Processes of the cervical spine and the Relationship Between UP and Vertebral Artery: Implication in Anterior Cervical Spine Surgery.

PURPOSE: The purpose of this study was to determine the relationship between the uncinate process and vertebral artery from a radiological view and to confirm the surgical safety margin in order to minimize the risk of vertebral artery injury during anterior cervical approaches. METHODS: We retrospectively reviewed computed tomography angiography of 205 patients by using a contrast-enhanced CTA protocol of the vertebral artery. Four kinds of images were simultaneously reconstructed to measure all the parameters associated with vertebral artery and uncinate process of cervical spine. RESULTS: The shortest distance from the UP's tip to the VA's medial border (p<0.001) was at the C-6 level (2.9±0.9mm on the left and 3.2±1.3 on the right), and the longest distance (p<0.001) was at the C-3 level on both sides. The distance between UP's tip and the medial border of the ipsilateral VA was statistically significantly different at each cervical level, and the right distance was larger than the left (p<0.05). We found the height of UP gradually increased from C-3 to C5-level and then decreased from C-5 to C-7 level for both sides. The mean distance between the medial borders of left UP and left VA was on average 7.5±1.4mm. The diameter of VA was on average 3.4±0.6mm on the left side and 3.2±0.7mm on the right. The diameter of the VA was statistically significantly different on both sides, and the left side was larger than the right (p<0.05). CONCLUSIONS: Detailed radiologic anatomy of vertebral artery and uncinate process was reviewed in this study. A deep understanding of the correlation between the uncinate process and vertebral artery is essential to perform anterior cervical spine surgery safely and ensure adequate spinal canal decompression.

Surgical Outcome in Patients with Traumatic and Atraumatic Optic Neuropathy Following Endoscopic Optic Nerve Decompression.

Endoscopic optic nerve decompression is a highly effective and reliable approach for patients with select cases of optic neuropathy. It reduces the hydrostatic pressure and helps in relieving the compressive forces within the intracanalicular portion of the optic nerve consequently preserving and arresting the deterioration of vision. The advantages of the endoscopic approach over other procedures include preservation of olfaction, quick recovery, lack of external scars and less morbidity. The objective of the study is to assess the surgical outcome of endoscopic optic nerve decompression in patients with traumatic and atraumatic optic neuropathy. The case records of consequent patients attending ENT department with defective vision due to traumatic and atraumatic causes were reviewed. The outcome was measured in terms of improvement in visual acuity by log MAR scale. Among the 14 patients studied, 57% were females and the median age of presentation was 33 years. As compared to preoperative baseline visual acuity, the overall improvement was achieved in 11 patients, with an effective rate of 78.5% postoperatively. Patients presenting with no light perception and residual vision had significant improvement in visual acuity after surgery. Trans-nasal endoscopic surgery helps in decompressing the optic nerve with proper exposure of the orbital apex and optic canal without any intracranial or intra-orbital complications. Further, being a minimally invasive procedure has great advantage in cases of optic neuropathy.

Paired and matched analysis of neurological outcomes in revision surgery for cervical myelopathy following delayed neurological decline.

Background: Delayed neurological decline may be experienced following successful decompression surgery for cervical myelopathy. Our objective was to analyze neurological recovery upon revision surgery with relation to the index procedure and a matched control. Methods: Fourteen patients underwent both primary and revision decompression at a single academic center. Peri-operative clinical, radiological, and surgical details were retrieved. Neurological outcomes [change in modified Japanese Orthopedic Association (mJOA), recovery ratio] following the second surgery were compared to (I) the primary operation and (II) a control subject receiving primary decompression matched for gender, age, mJOA score, and surgical approach. The minimum clinically important difference (MCID) in mJOA score was set at 2.5. Results: Revision decompressions were performed 6.8±4.2 years following the index surgery, when patients were 61.4±11.0 years of age. An increase in mJOA score of 2.7±2.0 following revision surgery was similar to that achieved after the primary operation (2.2±2.1, P=0.616). A recovery ratio of 38.1%±25.4% upon revision compared favorably to that following the primary operation (35.0%±37.4%, P=0.867). Non-inferiority testing between revision surgery and the first operation (P=0.02) demonstrated a similar capacity to achieve the MCID as did comparison with matched subjects (P<0.01). Conclusions: Patients were able to make up for lost neurological gains following revision surgery. Careful selection of cases for revision likely facilitated recovery. Recovery trajectories should be consolidated upon larger sample sizes allowing for identification of prognostic factors.

Does the use of tranexamic acid intraoperatively reduce postoperative blood loss and complications following biportal endoscopic lumbosacral decompression?

Background: Biportal endoscopic spine surgery is an effective minimally invasive technique for treating common lumbar pathologies. We aim to evaluate the impact of intraoperative tranexamic acid (TXA) use on postoperative blood loss in biportal endoscopic decompression surgery. Methods: Patients undergoing biportal endoscopic lumbar discectomies and decompressions either by same day surgery or overnight stay at a single institution beginning in October 2021 were prospectively enrolled. This study was non-randomized, non-blinded with the first cohort of consecutive patients receiving 1 g of intravenous TXA intra-operatively before closure and the second cohort of consecutive patients receiving no TXA. Exclusion criteria included any revision surgery, any surgery for the diagnosis of spinal instability, infection, tumor, or trauma, any contraindication for TXA. Results: Eighty-four patients were included in the study, with 45 (54%) receiving TXA and 39 (46%) not receiving TXA. Median follow-up was 168 days [interquartile range (IQR), 85-368 days]. There were no differences in patient or surgical characteristics between cohorts. Estimated blood loss (EBL) was similar (P=0.20), while post-operative drain output was significantly lower in the TXA cohort (P=0.0028). Single level discectomies had significantly less drain output as compared to 2 level unilateral laminotomy, bilateral decompression (ULBD) cases (P<0.005). Post-operative complications were similar, with low rates of wound complication (1.2%) and transient postoperative weakness (2.4%, P>0.99 for both). Oswestry disability index (ODI), visual analog scale (VAS) back and VAS leg scores decreased significantly; the absolute decrease in scores did not differ between groups (P=0.71, 0.22, 0.86, respectively). Conclusions: Systemic intraoperative TXA administration is associated with a significant decrease in post-operative blood loss in biportal spinal endoscopy, with no impact on the improvement in patient-reported outcomes (PROs) or rate of post-operative complications. Single level biportal discectomies had significantly less postoperative drainage with TXA and may not need drains postoperatively. Larger, randomized studies are necessary to evaluate the cost-effectiveness of TXA use in biportal spinal endoscopy.