Factors influencing slippage after microsurgical single level lumbar spinal decompression surgery - Are the psoas and multifidus muscles involved?

PURPOSE: Patients with lumbar spinal stenosis (LSS) require microsurgical decompression (MSD) surgery; however, MSD is often associated with postoperative instability at the operated level. Paraspinal muscles support the spinal column; lately, paraspinal volume has been used as a good indicator of sarcopenia. This study aimed to determine preoperative radiological factors, including paraspinal muscle volume, associated with postoperative slippage progression after MSD in LSS patients. METHODS: Patients undergoing single-level (L3/4 or L4/5) MSD for symptomatic LSS and followed-up for ≥ 5 years in our institute were reviewed retrospectively to measure preoperative imaging parameters focused on the operated level. Paraspinal muscle volumes (psoas muscle index [PMI] and multifidus muscle index [MFMI]) defined using the total cross-sectional area of each muscle/L3 vertebral body area in the preoperative lumbar axial CT) were calculated. Postoperative slippage in the form of static translation (ST) ≥ 2 mm was assessed on the last follow-up X-ray. RESULTS: We included 95 patients with average age and follow-up periods of 69 ± 8.2 years and 7.51 ± 2.58 years, respectively. PMI and MFMI were significantly correlated with age and significantly larger in male patients. Female sex, preoperative ST, dynamic translation, sagittal rotation angle, facet angle, pelvic incidence, lumbar lordosis, and PMI were correlated with long-term postoperative worsening of ST. However, as per multivariate analysis, no independent factor was associated with postoperative slippage progression. CONCLUSION: Lower preoperative psoas muscle volume in LSS patients is an important predictive factor of postoperative slippage progression at the operated level after MSD. The predictors for postoperative slippage progression are multifactorial; however, a well-structured postoperative exercise regimen involving psoas muscle strengthening may be beneficial in LSS patients after MSD.

The safety of perioperative antiplatelet continuation without selection biases in microsurgical decompression surgery for single level lumbar spinal stenosis and lumbar disc herniotomy.

PURPOSE: Each institution or physician has to decide on an individual basis whether to continue or discontinue antiplatelet (AP) therapy before spinal surgery. The purpose of this study was to determine if perioperative AP continuation is safe during single-level microsurgical decompression (MSD) for treating lumbar spinal stenosis (LSS) and lumbar disc hernia (LDH) without selection bias. METHODS: Patients who underwent single-level MSD for LSS and LDH between April 2018 to December 2022 at our institute were included in this retrospective study. We collected data regarding baseline characteristics, medical history/comorbidities, epidural hematoma (EDH) volume, reoperation for EDH, differences between preoperative and one-day postoperative blood cell counts (ΔRBC), hemoglobin (ΔHGB), and hematocrits (ΔHCT), and perioperative thromboembolic complications. Patients were divided into two groups: the AP continuation group received AP treatment before surgery and the control group did not receive antiplatelet medication before surgery. Propensity scores for receiving AP agents were calculated, with one-to-one matching of estimated propensity scores to adjust for patient baseline characteristics and past histories. Reoperation for EDH, EDH volume, ΔRBC, ΔHGB, ΔHCT, and perioperative thromboembolic complications were compared between the groups. RESULTS: The 303 enrolled patients included 41 patients in the AP continuation group. After propensity score matching, the rate of reoperation for EDH, the EDH volume, ΔRBC, ΔHGB, ΔHCT, and perioperative thromboembolic complication rates were not significantly different between the groups. CONCLUSION: Perioperative AP continuation is safe for single-level lumbar MSD, even without biases.

[Decompression fusion surgery and minimally invasive microsurgical decompression in patients with single-segment lumbar spinal stenosis]. / Sravnitel'nyi analiz rezul'tatov primeneniya metodik dekompressii so stabilizatsiei i minimal'no invazivnoi mikrokhirurgicheskoi dekompressii u patsientov s monosegmentarnym poyasnichnym spinal'nym stenozom.

There are few studies comparing clinical efficacy of decompression/fusion surgery (transforaminal lumbar interbody fusion (TLIF) + transpedicular interbody fusion) and minimally invasive microsurgical decompression (MMD) in patients with single-segment lumbar spinal stenosis. OBJECTIVE: To compare the results of TLIF + transpedicular interbody fusion and MMD in patients with single-segment lumbar spinal stenosis. MATERIAL AND METHODS: A retrospective observational cohort study included medical records of 196 patients (100 (51%) men, 96 (49%) women). Age of patients ranged from 18 to 84 years. Mean postoperative follow-up period was 20.1±6.7 months. Patients were divided into 2 groups: group I (control) included 100 patients who underwent TLIF + transpedicular interbody fusion, group II (study) included 96 patients who underwent MMD. We analyzed pain syndrome and working capacity using visual analogue scale (VAS) and Oswestry Disability Index (ODI), respectively. RESULTS: Analysis of pain syndrome in both groups after 3, 6, 9, 12 and 24 months clearly demonstrated stable relief of pain syndrome (VAS score) in the lower extremities. In group II, VAS score of lower back and leg pain was significantly higher in long-term follow-up period (after 9 months or more) compared to the 1st group (p<0.05). In long-term follow-up period (after 12 months), there was significant decrease in degree of disability (ODI score) in both groups (p<0.001) without between-group differences. We assessed achievement of treatment goal in 12 and 24 months after surgery in both groups. The result was significantly better in the 2nd group. At the same time, some respondents failed to achieve the final clinical goal of treatment in both groups (group I - 8 (12.1%), group II - 2 (3%) patients). CONCLUSION: Analysis of postoperative outcomes in patients with single-segment degenerative lumbar spinal stenosis revealed similar clinical effectiveness of TLIF + transpedicular interbody fusion and MMD regarding decompression quality. However, MMD was associated with less traumatization of paravertebral tissues, blood loss, fewer unwanted phenomena and earlier recovery.

Spinal cord compression in patients with mucopolysaccharidosis.

PURPOSE: Spinal abnormalities frequently occur in patients with mucopolysaccharidosis (MPS) types I, II, IV, and VI. The symptoms are manifold, which sometimes prolongs the diagnostic process and delays therapy. Spinal stenosis (SS) with spinal cord compression due to bone malformations and an accumulation of storage material in soft tissue are serious complications of MPS disease. Data on optimal perioperative therapeutic care of SS is limited. METHODS: A retrospective chart analysis of patients with MPS and SS for the time period 01/1998 to 03/2021 was performed. Demographics, clinical data, neurological status, diagnostic evaluations (radiography, MRI, electrophysiology), and treatment modalities were documented. The extent of the SS and spinal canal diameter were analyzed. A Cox regression analysis was performed to identify prognostic factors for neurological outcomes. RESULTS: Out of 209 MPS patients, 15 were included in this study. The most dominant type of MPS was I (-H) (n = 7; 46.7%). Preoperative neurological deterioration was the most frequent indication for further diagnostics (n = 12; 80%). The surgical procedure of choice was dorsal instrumentation with microsurgical decompression (n = 14; 93.3%). A univariate Cox regression analysis showed MPS type I (-H) to be associated with favorable neurological outcomes. CONCLUSION: Early detection of spinal stenosis is highly relevant in patients with MPS. Detailed neurological assessment during follow-up is crucial for timeous detection of patients at risk. The surgical intervention of choice is dorsal instrumentation with microsurgical decompression and resection of thickened intraspinal tissue. Patients with MPS type I (-H) demonstrated the best neurological course.

Influence of microsurgical decompression on segmental stability of the lumbar spine - One-year results in a prospective, consecutive case series using upright, kinetic-positional MRI.

BACKGROUND: Standard procedure in patients with lumbar spinal canal stenosis is decompression to relieve the neural structures. Clinical results generally show superiority compared to nonoperative therapy after an observation period of several years. However, there is still a question of postsurgical segmental stability and correlation to clinical findings. Therefore, the aim of this prospective study was to evaluate the clinical outcome in patients who underwent microsurgical decompression in lumbar spine and particularly to analyze intervertebral movement by use of upright, kinetic-positional magnetic resonance imaging (MRI) over a period of 12 months and then to correlate the clinical and imaging data with each other. METHODS: Complete clinical data of 24 consecutive participants with microsurgical decompression of the lumbar spine were obtained by questionnaires including visual analogue scale (VAS) for back and leg, Oswestry Disability Index (ODI), Roland-Morris Disability Questionnaire (RMDQ), Short-Form-36 (SF-36), walking distance and use of analgesics with assessment preoperatively and after 6 weeks and 12 months. At the same points of time all patients underwent upright, kinetic-positional MRI to measure intersegmental motion of the operated levels with determination of intervertebral angles and translation and to correlate the clinical and imaging data with each other. RESULTS: VAS for leg, ODI, RMDQ and physical component scale of SF-36 improved statistically significantly without statistically significant differences regarding intersegmental motion and horizontal displacement 6 weeks and 12 months after operation. Regression analysis did not find any linear dependencies between the clinical scores and imaging parameters. CONCLUSIONS: In awareness of some limitations of the study, our results demonstrate no increase of intersegmental movement or even instability after microsurgical decompression of the lumbar spine over a follow-up period of 12 months, which is equivalent to preservation of intervertebral stability. Furthermore, the magnitude of intervertebral range of motion showed no correlation to the clinical score parameters at all three examination points of time.

[Minimally invasive microsurgical decompression in patients with monosegmental lumbar spinal stenosis]. / Rezul'taty primeneniya minimal'no invazivnoi mikrokhirurgicheskoi dekompressii u patsientov s monosegmentarnym poyasnichnym stenozom.

Surgical treatment of degenerative lumbar spinal stenosis is an actual problem of modern spinal surgery and orthopedics. OBJECTIVE: To analyze the results of minimally invasive microsurgical decompression (MI-MD) in patients with monosegmental lumbar spinal stenosis. MATERIAL AND METHODS: A retrospective observational cohort study was performed. We analyzed medical records of patients who underwent MI-MD for monosegmental degenerative lumbar spinal stenosis. Clinical and objective results of MI-MD, as well as the types and prevalence of adverse clinical events were studied. RESULTS: The study included 96 medical records (50 (52%) males and 46 (48%) females aged 18-84 years). Analysis of pain in lower back and lower extremities in 3, 6, 9, 12 and 24 months after MI-MD showed a significant decrease of this indicator (p<0.001). There was significant improvement of capacity according to ODI score up to 5-12% in 72.9% of patients in early postoperative period (p=0.055). In delayed postoperative period, we also observed significant improvement of working capacity according to ODI score and gradual decrease in disability index (p<0.001). Adverse clinical events occurred in 6 (6.2%) patients. CONCLUSION: MI-MD is a highly effective surgical method for monosegmental lumbar spinal stenosis with minimal incidence of adverse clinical events.

Treatment results for lumbar epidural lipomatosis: Does fat matter?

PURPOSE: The lumbar epidural lipomatosis (LEL) is a rare disease that can cause sciatic pain syndrome or neurological deficits comparable to symptoms caused by a classical spinal canal stenosis. In severe cases surgical decompression was conducted. However, the outcome after decompressive surgery has only been investigated in small case series. In this study we compared the outcome of LEL patients after microsurgery with the outcome of patients with classical spinal stenosis (CSS). METHODS: Patients with LEL (n = 38) and patients with CSS (n = 51), who received microsurgical decompression, were followed in a prospective observational study for 3 years. The clinical results including the Oswestry Disability Index, Numeric Pain Rating Scale (NRS), Roland and Morris Disability Questionnaire, the Short Form-36 Score and the Walking Distance were analysed and compared between both groups. RESULTS: Patients with LEL improved significantly after microsurgical decompression in a 3-year follow-up concerning back pain, leg pain and pain-associated disability equal to patients with CSS (NRSback_LEL_preop. = 6.4; NRSback_CSS_preop. = 6.3; NRSback_LEL_3-years = 3.2; NRSback_CSS_3-years = 3.6; NRSleg_LEL_preop. = 6.3; NRSleg_CSS_preop. = 6.5; NRSleg_LEL_3-years = 2.5; NRSleg_CSS_3-years = 2.9; ODILEL_preop. = 52.7; ODICSS_preop = 51.8; ODILEL_3-years = 32.3; ODICSS_3-years = 27.6). The microsurgical decompression had a positive effect on the health-related quality of life, and patient satisfaction was high in both groups (LEL group-71%, CSS group-69%). CONCLUSIONS: LEL can influence the quality of life dramatically and cause a high degree of disability. A surgical decompression is a safe and effective procedure with a good clinical outcome comparable to the results in patients with an osteoligamentous spinal stenosis. Therefore, microsurgical decompression can be recommended in patients with LEL if conservative treatment fails. These slides can be retrieved under Electronic Supplementary Material.

Microsurgical decompression of tumor of a rare posterior third ventricular pathology.

Of the posterior third ventricular tumors, a papillary tumor of the pineal gland is a rare entity that originates from specialized ependymoma of the subcommissural organ. In this video narration, we present a case of a 33-year-old male with headaches and recent cognitive decline due to a posterior third ventricular lesion. The patient underwent a posterior interhemispheric approach, and a gross-total decompression was achieved with no signs of recurrence in a 2-year follow-up period. With this case we highlight the microsurgical technique employed for decompressing tumors of the posterior third ventricular region with preservation of eloquent structures and draining veins. The video can be found here: https://youtu.be/o0WbyOqmtX0 .

Facial nerve decompression of a PICA vessel loop: A case report.

INTRODUCTION AND IMPORTANCE: Facial nerve palsy is a common condition with various etiologies. However, compression due to a vessel loop is an exceptionally rare cause. This case report highlights the unusual presentation and management of facial nerve palsy caused by vascular compression, emphasizing the importance of considering rare etiologies in persistent cases. CASE PRESENTATION: We describe the case of a young female patient who presented with a history of right blepharospasm and facial muscle twitching for several years. Cranial magnetic resonance imaging (MRI) revealed a posterior inferior cerebellar artery (PICA) vessel loop compressing the exit of the acoustofacial bundle at the level of the brainstem. CLINICAL DISCUSSION: The patient's condition necessitated a microscopic surgical decompression to relieve the compression on the facial nerve. During the procedure, the facial nerve was freed and cushioned using Teflon. This intervention highlights the potential for surgical resolution in cases of facial nerve palsy caused by vascular compression, despite its rarity. CONCLUSION: Postoperatively, the patient was free from blepharospasm and showed significant clinical improvement in facial muscle control. This case underscores the importance of considering vascular compression in the differential diagnosis of persistent facial nerve palsy and demonstrates the efficacy of surgical decompression in such cases.

Management of patients with a neurovascular conflict involving the optic nerve and a non-diseased intracranial artery: Three cases.

Introduction: Determining whether a neurovascular conflict (NVC) involving the anterior visual pathway (AVP) and a non-diseased intracranial artery is amenable for microvascular decompression is challenging. Moreover, it is unclear whether microvascular decompression of the optic nerve is an effective therapy. Research question: What are the outcomes of different treatment strategies for NVCs involving the AVP and a non-diseased intracranial artery? Material and methods: Data on patients with symptomatic NVCs involving the AVP and a non-diseased intracranial artery was collected and included treatment and outcome parameters. The case series was drafted in accordance with the CARE guidelines. Results: Three patients aged 53,53 and 55 visited our out-patient clinic with a suspected symptomatic NVC between the optic nerve and a non-diseased intracranial artery. A conservative treatment was opted for in the first patient aimed at treating her glaucoma, with temporary improvement of symptoms. Microvascular decompression of the optic nerve was performed in two patients. One operated patient developed post-operative complications resulting in posterior circulation perfusion decline, while the other experienced a worse tunnel vision with a decrease in visual acuity. Discussion and conclusion: The diagnosis of a symptomatic NVC between the AVP and a non-diseased intracranial artery should be considered with caution, i.e. after exclusion of all other causes. Microvascular decompression can be performed but does not necessarily improve symptoms. A better understanding of the pathophysiological mechanisms underlying these NVCs is warranted to determine the benefit of microvascular decompression of the optic nerve.

Influence of the sagittal spinal profile type on the long-term outcome of patients with symptomatic lumbar spinal stenosis after microsurgical decompression.

OBJECTIVE: Microsurgical decompression for patients with symptomatic lumbar spinal stenosis (LSS) has demonstrated long-term improvement concerning pain and function. Nonetheless, a considerable proportion of these patients do not experience satisfactory alleviation of symptoms. Previous studies have not found a direct influence of single sagittal parameters on patient outcomes. However, recent research indicates that a composite of parameters, presented in specific sagittal profile types (SPTs) that were defined by Roussouly and colleagues, may affect these outcomes. This study aims to investigate the impact of SPT on long-term outcomes of patients with LSS following microsurgical decompression. METHODS: This study is a prospective clinical observation. Patients with symptomatic LSS, who underwent microsurgical treatment and had long-term follow-up data for at least 36 months, were included. Patients with spinal deformity, fractures, or significant instability were excluded. Outcomes were measured using the numeric rating scale for pain, 36-Item Short Form Health Survey for quality of life, walking distance, Oswestry Disability Index, Roland-Morris Disability Questionnaire, and Odom's criteria. SPT was determined in blinded fashion by using preoperative long standing radiographs. RESULTS: The initial population of this observational study consisted of 128 patients, with long-term results available for 87 individuals, including 24 patients with SPT1, 20 with SPT2, 27 with SPT3, and 16 with SPT4. The average age was 70 years, with a slight male majority (56.3%) and a mean BMI of 27.9 kg/m2. After a median follow-up of 48 months, all groups showed significant improvement in walking distance, leg pain, and disability. Overall, 75% reported satisfaction with the surgery. However, patients with SPT1, which is characterized by low sacral slope and specific spinal curvatures, experienced significantly less improvement in back pain (p = 0.018) and related disability (p = 0.030), and lower satisfaction compared to other SPT groups (p = 0.008). CONCLUSIONS: The sagittal spinal type is influencing the long-term outcome of patients suffering from symptomatic LSS. Patients with a combination of a flat sacral slope and a low overall lumbar lordosis with a high lordosis in the lower lumbar spine (i.e., spinal SPT1) showed worse outcome concerning back pain and had decreased satisfaction with surgery than comparable subjects from other SPT groups. Consequently, the authors recommend the assessment of sagittal spinal types in patients diagnosed with symptomatic spinal stenosis prior to decompression surgery. Inclusion of SPT in the preoperative consultation process can provide valuable insights, potentially guiding practitioners to more tailored patient counseling.

Ectatic vertebral artery associated medullary compression treated with microvascular decompression: a case report and review of literature.

BACKGROUND: Vertebral artery compression syndrome is a rare condition defined as the clinical presentation of dizziness, vertigo, ataxia, dysarthria, dysphagia, progressive or acute paralysis, hemisensory loss, and cervical myelopathy secondary to compression of the medulla and upper spinal cord by the vertebral artery. CASE DESCRIPTION: Here we describe a 57-year-old Mexican-American male with bulbar symptoms, positional vertigo, and diplopia. The patient's symptoms were managed through microsurgical decompression of the medulla utilizing a far lateral transcondylar approach. The patient reported clinical improvement on follow-up. CONCLUSION: This case underscores the clinical complexity and heterogeneity of this rare neurovascular pathology and the importance of elucidating the pathophysiological mechanisms underlying the symptomatic presentation of vertebral artery compression syndrome.

Long-Term Changes in Sagittal Balance After Microsurgical Decompression of Lumbar Spinal Canal Stenosis in Elderly Patients: A Follow-Up Study for 5-Years After Surgery.

OBJECTIVE: The purpose of this study is to investigate long-term changes in spinal sagittal balance after microsurgical decompression in lumbar canal stenosis (LCS). METHODS: Fifty-two patients who underwent microsurgical decompression for symptomatic single level L4/5 spinal canal stenosis at our hospital were included in the study. All patients had standing full spine radiographs taken preoperatively, 1 year postoperatively, and 5 years postoperatively. Spinal parameters including sagittal balance were measured from the obtained images. First, preoperative parameters were compared with 50 age-matched asymptomatic volunteers. Next, the parameters before and after surgery were compared to examine long-term changes. RESULTS: Sagittal vertical axis (SVA) was significantly increased in the LCS cases compared to the volunteers (P = 0.03). Postoperative lumbar lordosis (LL) was significantly increased (P = 0.03). Postoperative mean SVA decreased but the difference was not significant (P = 0.12). Although there was no correlation between preoperative parameters and the Japanese Orthopedic Association score, postoperative pelvic incidence (PI)-LL and pelvic tilt changes correlated with changes in Japanese Orthopedic Association score (PI-LL; P = 0.0001, pelvic tilt; P = 0.04). However, after 5 years of surgery, LL decreased and PI-LL increased (LL; P = 0.08, PI-LL; P = 0.03). Sagittal balance began to deteriorate but was not significant (P = 0.31). At 5 years postoperatively, 18 of 52 patients (34.6%) were found to have L3/4 adjacent segment disease. Cases with adjacent segment disease showed significantly worse SVA and PI-LL (SVA; P = 0.01, PI-LL; P < 0.01). CONCLUSIONS: In LCS, lumbar kyphosis improves and sagittal balance tends to improve after microsurgical decompression. However, after 5 years, adjacent intervertebral degeneration occurs more frequently and sagittal balance begins to deteriorate in about one third of cases.

[Lumbar spinal stenosis]. / Lumbale Spinalkanalstenose.

Lumbar spinal stenosis (LSS) represents a frequent degenerative condition, however, striking a clear correlation between typical symptoms and imaging features remains a challenge. Reasons are a high prevalence of radiological LSS in the older population, a considerable percentage of asymptomatic LSS and the existence of differential diagnoses with similar symptomatology. This discrepancy also affects the outcomes - especially of surgically treated patients with LSS. When considering surgical decompression of LSS, the decision with regards to additive instrumentation and/or fusion remains a controversial point of discussion, in particular at the presence of degenerative spondylolisthesis. Recent, well-designed studies, however, clearly point towards a non-inferiority of decompression alone as opposed to the more invasive strategies.

Case Report: Direct Visualization of the Nervus Intermedius During the Microvascular Decompression Procedure: Should We Take It Seriously?

Background: Nervus intermedius neuralgia (NIN), known as geniculate neuralgia (GN), is an uncommon cranial nerve disease caused by an offending vessel compressing the nervus intermedius (NI). Microvascular decompression (MVD) has now become a valued treatment approach for NIN because it can resolve neurovascular conflict (NVC) at the root entry zone of the NI. In the era of continuously optimizing and improving the surgical technique of MVD, further minimization of all possible postoperative complications is not only welcome but also necessary. Objective: The aim of this work is to assess the postoperative outcome of direct visualization of the NI during the MVD procedure. Methods: This study retrospectively reviewed the clinical records of a group of seven consecutive patients with NIN who underwent MVD in the period of 2013-2020 in our clinic and 16 studies reported NIN patients who underwent MVD in the period of 2007-2020. Results: In total, 91.3% of all patients experienced immediate and complete relief of cranial neuralgia after MVD. Six of 23 patients have experienced direct visualization of the NI intraoperatively, and 66.7% of those patients had complications such as facial paralysis, dysacousia, or a combination of these conditions postoperatively. Slight surgical approach-related complications such as complaints associated with excessive drainage of cerebrospinal fluid (CSF), nausea and vertigo, and delayed wound union were observed in 80% of the remaining 15 patients, and these symptoms are totally relieved in the telephone and outpatient follow-up after 6 months. Conclusion: Our case series shows that MVD produced immediate pain relief in the majority of NIN patients. MVD carries surgical risk, especially in patients who experience direct visualization of the NI after mechanical stretch and blunt dissection in surgical procedures. Attempts to avoid mechanical stretch and blunt dissection of the compressed nerve were important for intraoperative neuroprotection, especially facial nerve protection.

A Case of Dural Herniation of the Cauda Equina Caused by Enlarged Spinal Subdural Extra-arachnoid Hygroma Following Lumbar Microsurgical Decompression: Case Report.

We experienced a rare case of transdural herniation of cauda equina caused by increased pressure with spinal subdural extra-arachnoid hygroma (SSEH) following lumbar microsurgical decompression. A 68-year-old woman presented with complaints of right leg pain and intermittent claudication. By the diagnosis of L2/3 lumbar spinal stenosis, microsurgical decompression was performed. The surgery was successful with no issues arising such as damage to the dura mater. Lumbar magnetic resonance imaging (MRI) performed 8 days after the surgery confirmed asymptomatic SSEH on the ventral side of the cauda equina. However, posterior cervical pain and lower back pain developed 32 days after the surgery. Lumbar MRI demonstrated that SSEH had markedly increased and advanced from the lumbar spine to the cranium, compressing the spinal cord posteriorly. In addition, herniation of the cauda equina was confirmed in the dura. An emergency surgery was performed. The herniated cauda equina was fully positioned in the dural sac, and the arachnoid membrane with accumulation of spinal fluid on the ventral side was fenestrated. Immediately after the surgery, the patient's symptoms disappeared. Sufficient caution is required regarding the possibility of SSEH associated with spinal failed back surgery syndrome as it can become excessively enlarged, leading to a poor prognosis.

Are degenerative spondylolisthesis and further slippage postoperatively really issues in spinal stenosis surgery?

Background and aims Opinions diverge concerning the prognostic importance of preoperative degenerative spondylolisthesis in patients with lumbar spinal stenosis, as well as the significance of further slippage post-operatively following decompression alone. However, a slip is only one among several factors related to the topic, e.g. duration and intensity of back and leg pain, pre-operative walking ability, number of levels operated and not least the experience of the surgeon. Our aim was to take all of the above-mentioned factors into consideration when analysing the patients' clinical outcome, reported as Change in back pain, Change in leg pain, Overall satisfaction and Change in walking ability, with special emphasis on the possible importance of pre- and/or post-operative degenerative spondylolisthesis. Methods We studied 200 consecutive patients, mean follow-up time 81 months (range 62-108). Before treatment and on the follow-up occasion all patients answered the SF-36 questionnaire and assessed their back and leg pain on a visual analogue scale (VAS). At follow-up the patients were asked about possible changes in back and leg pain (completely free, much better, somewhat better, unchanged, somewhat worse, much worse) and whether they were; satisfied with the outcome, in doubt or not satisfied. Before treatment and at follow-up the presence or not of degenerative spondylolisthesis was determined in the lateral view on a plain X-ray or MRI. By use of a microsurgical technique decompression was achieved in all patients by bilateral laminotomy not sparing the midline ligaments, irrespective of a degenerative spondylolisthesis or not. Eight surgeons with different surgical experience performed the operations. Four separate multivariate analyses were conducted, one for each clinical outcome. The Lasso method was used for variable selection and multiple imputation was applied to handle missing values. Results At follow-up 78.5% of the patients were completely satisfied with the outcome. Minimal clinical important difference (MCID) was achieved for 69% of the patients. Before surgery 28 patients were able to walk more than 1 km compared to 111 at follow-up. The reoperation rate at 6.8 years was 12% further decompressions and 2.5% fusions at the index level. Post-operative slippage was equally common in patients with and without a preoperative slip (around 30%). There were no notable differences in outcome in patients with and without a preoperative slip and no effect of further slippage at the index or another level post-operatively. Nor could the statistical analysis show any of the other covariates (age, gender, duration and intensity of back and leg pain, pre-operative walking ability or number of levels operated) to be of statistically significant importance for predicting the outcome. In the univariate statistical analysis differences were found between the patients of individual surgeons regarding satisfaction, pain improvement, and reoperation rates in favour of surgical experience, which were, however, not statistically significant in the multivariate analysis. Conclusions None of the covariates, including pre-operative spondylolisthesis and further slippage post-operatively, were statistically significant for predicting the clinical outcome. Implication Our results provide no evidence for adding fusion to the decompression.

Bow Hunter's Syndrome: Complete Microsurgical Decompression of Vertebral Artery by Far Lateral Retrocondylar Approach: 3-Dimensional Operative Video.

This 50-yr-old man had a 15-yr history of presyncopal episodes that were precipitated by turning his head to the right, and had worsened recently. Cerebral angiogram demonstrated complete cessation of anterograde flow in left vertebral artery (VA) at the level of the C1 sulcus arteriosus while turning head to right, indicating dynamic compression at the C1 level. Patient underwent left extreme lateral retrocondylar approach, partial C1 laminectomy and opening of the C1 foramen with complete microsurgical decompression of the VA. After skin incision, meticulous muscle dissection was performed and superior and inferior oblique muscles were disconnected from the tubercle of C1. The VA was exposed, and three areas of constriction were visible, first at the atlanto-occipital membrane laterally; second, located more medially as the artery curved around the occipital condyle to enter the posterior fossa; and third, located anterior to C2 nerve root. The artery was dissected from all the surrounding tissues, preserving the C2 nerve root, and the Cl foramen was opened completely. The Cl lamina was also partially resected and grooved to allow free placement of the VA. The VA was also decompressed near the C2 foramen. Postoperative computed tomography angiogram of the head and neck showed complete decompression of VA. The patient had no episodes of presyncope or dizziness while turning head to right and his mRs was 0 at 8 mo follow up. This 3D video shows the technical nuances of decompression of V3 segment of VA in bow hunters's syndrome. Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.