The First Pituitary Proteome Landscape From Matched Anterior and Posterior Lobes for a Better Understanding of the Pituitary Gland.

To date, very few mass spectrometry (MS)-based proteomics studies are available on the anterior and posterior lobes of the pituitary. In the past, MS-based investigations have focused exclusively on the whole pituitary gland or anterior pituitary lobe. In this study, for the first time, we performed a deep MS-based analysis of five anterior and five posterior matched lobes to build the first lobe-specific pituitary proteome map, which documented 4090 proteins with isoforms, mostly mapped into chromosomes 1, 2, and 11. About 1446 differentially expressed significant proteins were identified, which were studied for lobe specificity, biological pathway enrichment, protein-protein interaction, regions specific to comparison of human brain and other neuroendocrine glands from Human Protein Atlas to identify pituitary-enriched proteins. Hormones specific to each lobe were also identified and validated with parallel reaction monitoring-based target verification. The study identified and validated hormones, growth hormone and thyroid-stimulating hormone subunit beta, exclusively to the anterior lobe whereas oxytocin-neurophysin 1 and arginine vasopressin to the posterior lobe. The study also identified proteins POU1F1 (pituitary-specific positive transcription factor 1), POMC (pro-opiomelanocortin), PCOLCE2 (procollagen C-endopeptidase enhancer 2), and NPTX2 (neuronal pentraxin-2) as pituitary-enriched proteins and was validated for their lobe specificity using parallel reaction monitoring. In addition, three uPE1 proteins, namely THEM6 (mesenchymal stem cell protein DSCD75), FSD1L (coiled-coil domain-containing protein 10), and METTL26 (methyltransferase-like 26), were identified using the NeXtProt database, and depicted tumor markers S100 proteins having high expression in the posterior lobe. In summary, the study documents the first matched anterior and posterior pituitary proteome map acting as a reference control for a better understanding of functional and nonfunctional pituitary adenomas and extrapolating the aim of the Human Proteome Project towards the investigation of the proteome of life.

Clinical analysis of surgical outcome of 89 patients having large cerebral arteriovenous malformations.

OBJECTIVE: The article analyzes the clinical features, morphological characteristics, surgical subtleties and long-term outcome of surgery in 89 cases of 'large' sized AVMs. MATERIALS AND METHODS: During the period 2004 to 2022, 89 cases of 'large' arteriovenous malformations were operated in the neurosurgery departments of the authors. Large AVMs were defined as those that were more than 4 cm on either lateral or antero-posterior view of digital subtraction angiogram. The factors that determined the extent of surgical difficulties included site and eloquence of the area, number of feeding vascular territories and draining veins, degree and rate of flow, presence of flow-related aneurysms, and the physical nature of the arteriovenous malformation. RESULTS: There were 59 males and 30 females and the average age was 32 years. Headache, giddiness and convulsions were the common presenting complaints. Six patients were unconscious after surgery. Of these, five patients died in the immediate post-operative period and one patient gradually recovered. Additionally, seven patients developed unilateral limb weakness that included hemiplegia (4 patients) and hemiparesis (3 patients) following surgery. Clinical follow-up ranged from 6 months to 18 years (average 43 months). All surviving patients are leading normal and essentially symptom free life and have recovered from their symptoms of headache, convulsions and giddiness. CONCLUSIONS: Large AVMs are amenable to 'curative' surgery with 'acceptable' results. The surgery can be challenging and appropriate case selection that is based on the surgeons experience is vital and decisive.

Evolving Concepts of Craniovertebral and Spinal Instability.

Weakness of the muscles of the nape of the neck and back of the spine and its related instability is the nodal point of pathogenesis of a number of clinical and pathological events at the craniovertebral junction and the spine. Whilst acute instability results in sudden and relatively severe symptoms, chronic or long-standing instability is associated with a range of musculoskeletal and structural spinal alterations. Telescoping of the spinal segments results in "vertical" spinal instability in the subaxial spine and central or axial atlantoaxial instability (CAAD) at the craniovertebral junction. Instability in such cases might not be observed on dynamic radiological imaging. Chiari formation, basilar invagination, syringomyelia, and Klippel-Feil alteration are some of the secondary alterations as a result of chronic atlantoaxial instability. Radiculopathy/myelopathy related to spinal degeneration or ossification of posterior longitudinal ligament appears to have their origin from vertical spinal instability. All the secondary alterations in the craniovertebral junction and subaxial spine that are traditionally considered pathological and to have compressive and deforming role are essentially protective in nature, are indicative of instability, and are potentially reversible following atlantoaxial stabilization. Stabilization of unstable spinal segments is the basis of surgical treatment.

Central Atlantoaxial Dislocation: Presenting Symptoms, Diagnostic Parameters, and Surgical Treatment from Reports on 15 Surgically Treated Patients.

AIM: This chapter reviews the clinical entity of central or axial atlantoaxial instability (CAAD). MATERIAL AND METHODS: From January 2018 to November 2020, 15 patients were identified as having CAAD, wherein there was no atlantoaxial instability when analyzed by conventional radiological parameters and wherein there was no evidence of neural or dural compression due to the odontoid process. The patients were identified as having atlantoaxial instability on the basis of the alignment of facets on lateral profile imaging and a range of telltale clinical and radiological indicators. The clinical statuses of the patients were recorded both before and after surgical treatment by using the specially designed Goel symptom severity index and visual analog scale (VAS) scores. All patients were treated via atlantoaxial fixation. RESULTS: There were six men and nine women ranging in age from 18 to 45 years (average: 37 years). The presenting clinical symptoms were relatively subtle and long-standing. Apart from symptoms that are generally related to neural compromise at the craniovertebral junction, a range of nonspecific cranial and spinal symptoms were prominent. The follow-up time after surgery ranged from 6 to 34 months. All patients showed early postoperative and sustained clinical recovery. CONCLUSIONS: The correct diagnosis and appropriate surgical treatment of CAAD can provide an opportunity for quick and lasting clinical recovery.

Central or axial atlantoaxial dislocation and craniovertebral junction alterations: a review of 393 patients treated over 12 years.

OBJECTIVE: The authors reviewed their scientific publications and updated their clinical material obtained over the last 12 years for cases of central or axial atlantoaxial dislocation (CAAD) identified in the presence of craniovertebral musculoskeletal and/or neural alteration(s). The management implications of diagnosing and treating CAAD are highlighted. METHODS: During a 12-year period, CAAD was diagnosed in 393 patients with craniovertebral junction-related musculoskeletal and neural alterations who underwent atlantoaxial fixation. No bone decompression was done. All CAAD-related craniovertebral junction structural changes were identified to have a naturally protective role. Hence, in this paper the term "craniovertebral alterations" is used for "craniovertebral junction anomalies" and the term "Chiari formation" is used instead of the commonly used term "Chiari malformation." RESULTS: The major radiological diagnosis was determined either singly or in cohort with one or more of other so-called pathological entities that included Chiari formation (367 cases), syringomyelia with Chiari (306 cases), idiopathic syringomyelia (12 cases), type B basilar invagination (147 cases), bifid arch of the atlas (9 cases), assimilation of the atlas (119 cases), C2-3 fusion (65 cases), Klippel-Feil alteration (4 cases), and dorsal kyphoscoliosis (15 cases). The follow-up period ranged from 6 to 155 months. Clinical improvement was observed in all patients. CONCLUSIONS: Understanding and treating CAAD may have significant implications in the surgical treatment of a number of clinical entities. The gratifying clinical outcomes obtained in patients after atlantoaxial fixation, without any type of decompression involving bone or soft-tissue resection, consolidate the concept that atlantoaxial instability has a defining role in the pathogenesis.

Metabolomics Profiling of Pituitary Adenomas by Raman Spectroscopy, Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy, and Mass Spectrometry of Serum Samples.

To date, no studies are available in which pituitary adenomas (PAs) have been studied using techniques like confocal Raman spectroscopy, attenuated total reflection-Fourier transform infrared (FT-IR), and liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the same serum samples. To understand the metabolomics fingerprint, Raman spectra of 16 acromegaly, 19 Cushing's, and 33 nonfunctional PA (NFPA) and ATR-FTIR spectral acquisition of 16 acromegaly, 18 Cushing's, and 22 NFPA patient's serum samples were acquired. Next, Principal component-based linear discriminant analysis (PC-LDA) models were developed, Raman spectral analysis classified acromegaly with an accuracy of 79.17%, sensitivity of 75%, and specificity of 81.25%, Cushing's with an accuracy of 66.67%, sensitivity of 100%, and specificity of 52.63%, and NFPA with an accuracy of 73.17%, sensitivity of 75%, and specificity of 72.73%. ATR-FTIR spectral analysis classified acromegaly with an accuracy of 95.83%, sensitivity of 100%, and specificity of 93.75%, Cushing's with an accuracy of 65.38%, sensitivity of 87.5%, and specificity of 55.56%, and NFPA with an accuracy of 70%, sensitivity of 87.5%, and specificity of 43.75%. In either of the cases, healthy individual cohorts were clearly segregated from the disease cohort, which identified differential regulated regions of nucleic acids, lipids, amides, phosphates, and polysaccharide/C-C residue α helix regions. Furthermore, LC-MS/MS-based analysis of sera samples resulted in the identification of various sphingosine, lipids, acylcarnitines, amino acids, ethanolamine, choline, and their derivatives that differentially regulated in each tumor cohort. We believe cues obtained from the study may be used to generate the metabolite-based test to diagnose PAs from serum in addition to conventional techniques and also to understand disease biology for better disease management, point of care, and improving quality of life in PA patients.

Hangman's fracture: a clinical review based on surgical treatment of 15 cases.

This is a retrospective analysis of cases with hangman's fracture. The subject of 'hangman's fracture' has been elaborately evaluated in the literature. The authors propose an alternative format of surgical treatment that is based on modification of existing classification schemes. During the period 2015 to March 2020, 15 patients having hangman's fracture were identified and were surgically treated. The clinical condition was classified on the basis of American Spinal Injury Association scale (ASIA scale) and VAS parameters. The patients were classified into 4 groups depending on the presence (or absence) of atlantoaxial and/or C2-3 instability. Surgical decisions were guided by the proposed classification. Clinical evaluation and dynamic CT scan were done at follow-up visits. During the average follow-up of 26 months, all patients are essentially asymptomatic. There was marginal restriction of extent of neck movements in all cases. There was solid bone fusion in all cases. The proposed novel classification scheme based on the presence of atlantoaxial and C2-3 instability assisted in directing the treatment strategy of hangman's fracture.

Yoko Kato: the silent warrior of neurosurgery.

The presence of women in neurosurgery is slowly but surely gaining momentum as many aspiring young female medical residents are being enticed by this fascinating branch. History is rife with the struggles of pioneering women who entered the neurosurgical profession against all odds, formed a firm foothold, and built a legacy for generations to emulate. Prof. Yoko Kato has spent her entire lifetime in the service of neurosurgery and taking it to the remotest corners of the world. Her persistence and conviction have made her one of the most admired neurosurgeons in the world and the most loved neurosurgeon for those in the less privileged countries. She has inspired and trained an entire generation of neurosurgeons. Her contributions will always be a glorious chapter in the world book of neurosurgery.

Cabergoline may act as a radioprotective agent in Cushing's disease.

CONTEXT: Conventional fractionated radiotherapy (CRT) achieves control of pathological hypercortisolism in 75%-80% of patients with persistent or recurrent Cushing's disease (CD), over a mean period of 18-24 months. Medical therapy is recommended as bridge therapy while awaiting RT effect. OBJECTIVE: To determine long-term outcome of CRT and its predictors in CD patients. DESIGN, SETTING AND PATIENTS: This is a retrospective case record analysis of 42 patients with CD who received CRT as a treatment modality and had at least 12 months post-RT follow-up. The dose delivered was 45 Gy in 25 fractions over 5 weeks. Demographic details, hormonal evaluation and radiological data were extracted from case records. Dexamethasone suppressed cortisol at cut-off of 1.8 µg/dL was used to define remission or recurrence. Possible predictors for remission and recurrence were analysed. RESULTS: The mean age at the time of CRT administration was 23.7 ± 10.7 (range: 12-48) years. A total of 29 (69%) patients achieved remission 26.5 ± 28.5 (median: 18, range: 3-120) months after RT, while 13 (31%) patients had persistent disease at last follow-up. There were no significant predictors of disease remission after CRT. Six (20.7%) patients had recurrence after a documented initial remission. Recurrence occurred 66.6 ± 25.9 (median: 74; range: 18 to 90) months after documented remission. Recurrence of the disease was exclusively seen in patients who received peri-RT cabergoline. Peri-CRT use of cabergoline was significantly associated with increased recurrence rates (P = .016). CONCLUSION: Use of cabergoline in the peri-CRT period did not affect initial remission after CRT but was associated with increased recurrence after initial remission in CD.

Atlantoaxial Fixation for Treatment of Chiari Formation and Syringomyelia with No Craniovertebral Bone Anomaly: Report of an Experience with 57 Cases.

AIM: In this paper we evaluate the role of atlantoaxial instability in the pathogenesis of Chiari formation type I and the role of atlantoaxial stabilization for treatment of this condition in cases with no obvious bone malformation in the region of the craniovertebral junction. MATERIALS, METHODS AND RESULTS: During the period from January 2010 to July 2016, we identified 57 cases of Chiari formation where there was no bone malformation or evidence of craniovertebral junction instability that could be diagnosed on the basis of an abnormal increase in the atlantodental interval on dynamic imaging. Forty-eight of these patients had syringomyelia. The average duration of follow-up was 42 months. There were 30 males and 27 females in the series. The ages of the patients ranged from 4 to 57 years. The Japanese Orthopaedic Association (JOA), visual analogue scale (VAS) and Goel clinical grading systems were used to assess the patients' clinical status. Atlantoaxial instability was diagnosed on the basis of vertical mobility of the odontoid process on dynamic radiographs, facetal malalignment on imaging or direct bone handling during the surgical procedure. Surgical treatment was achieved using atlantoaxial fixation. Foramen magnum decompression or syrinx manipulation was not done. All patients had immediate postoperative and sustained clinical symptomatic recovery. A reduction in the size of the syrinx was observed in ten patients and regression of tonsillar herniation was observed in 12 of 23 cases in which postoperative magnetic resonance imaging (MRI) was possible. CONCLUSION: Atlantoaxial instability is the prime factor in the genesis of Chiari formation even when there is no bone abnormality in the craniovertebral junction.

Lumbar canal stenosis: analyzing the role of stabilization and the futility of decompression as treatment.

OBJECTIVEThe authors report their current experience with their previously published novel form of treatment in 70 cases of lumbar canal stenosis. The treatment consisted of only fixation of the spinal segments by the transarticular screw fixation technique. No bone, ligament, osteophyte, or disc resection was done for spinal canal and neural foraminal decompression. The proposed treatment is based on the concept that vertical instability that results in telescoping of the facets on physical activity forms the nodal point of pathogenesis of lumbar canal stenosis.METHODSDuring the period June 2014 to May 2018, 70 patients presenting with the classically described symptoms of lumbar canal stenosis were treated surgically by only fixation of involved spinal segments. Apart from clinical and radiological guides, instability was diagnosed on the basis of physical observation of the status of articulation by direct manipulation of bones of the region. The operation involved transarticular insertion of 2 or 3 screws for each articulation. The Oswestry Disability Index and visual analog scale were used to assess the patients before and after surgery and at follow-up. Additionally, a personalized patient satisfaction score was used to assess the outcome of surgery.RESULTSClinical symptomatic recovery was observed in all patients in the immediate postoperative period. During the average follow-up period, 100% of patients had varying degrees of symptomatic relief. The patient satisfaction score suggested that all patients were very satisfied with the surgical procedure. The transarticular fixation technique provided strong spinal segment fixation and a reliable ground for bone arthrodesis. No patient needed any additional modality of treatment or reoperation for recurrence of symptoms.CONCLUSIONSSpinal instability is the nodal point of pathogenesis of spinal degeneration-related lumbar canal stenosis. Only fixation of the involved spinal segments is necessary-decompression by bone or soft-tissue resection is not necessary.

Atlantoaxial instability associated with pan cervical vertebral fusion: Report on management of 4 cases.

We report a series of four patients aged 4, 5, 14, and 27 years (1 male and 3 female patients) with severe shortening of the neck and torticollis since early childhood who presented with complaint of pain in the nape of neck as the primary symptom. All four patients had relatively well preserved neurological functions. One patient had vertical mobile and reducible atlantoaxial dislocation, and 3 patients had anteroposterior mobile and reducible dislocation. There was assimilation of atlas in 1 patient. The arch of atlas was bifid in 3 patients. Two patients underwent atlantoaxial fixation. Both the patients were relieved of neck pain after their surgery. The potential surgical difficulties due to the presence of severe shortening of neck height and marginal presenting symptoms favored conservative observation in the other 2 patients. Follow-up ranged from 6 to 84 months. All patients are functionally and socially active.

Olfactory groove meningiomas: An analysis based on surgical experience with 129 cases.

OBJECTIVE: The surgical strategy and outcome for 129 patients operated for an olfactory groove meningioma is retrospectively analyzed. MATERIAL AND METHODS: One hundred and twenty nine patients with an olfactory groove meningioma operated between the years 1987 and 2016 were analyzed on the basis of clinical and radiological factors that appeared to affect the conduct of surgery and its outcome. Each factor was given points, and the points were added to obtain a score. On the basis of the score, the tumors were divided into three grades. The grades determined the difficulties that could be anticipated during surgery. In the initial part of the series, a bifrontal craniotomy was done to resect the tumor in all patients. In the later half of the series, majority of the patients were operated by the use of a unifrontal craniotomy. The aim of surgery was to resect the tumor completely. RESULTS: Total tumor resection was achieved in 86 patients, and subtotal tumor resection with less than 10% tumor left behind was achieved in 43 patients. Seven patients died in the immediate postoperative period. All patients where a subtotal tumor resection was done and where the patient died after surgery had a higher grade tumor. The average follow-up period was 82 months. There was non-symptomatic recurrence in 11 patients. CONCLUSIONS: The location and size of the tumor, extent and duration of visual symptoms, extent of tumor adjoining cerebral edema, encasement of anterior cerebral artery complex and extension in the extracranial compartment were more important factors that affected the outcome of surgery.

Three-dimensional model printing for surgery on arteriovenous malformations.

AIM: Surgery for intracranial complex vascular malformations can be quite exigent and involves considerable preoperative planning. Here, we present the advantages of using three-dimensional (3D) printed models as a preoperative investigational modality. MATERIAL AND METHODS: 3D printed models were made from thin-slice computed tomography (CT) angiography scans of 6 patients with arteriovenous malformations over an18-month period from August 2015 to December 2016. The locations of the arteriovenous malformations were in the Sylvian fissure in 1 patient, posterior frontal region in 2 patients, subfrontal region in 1 patient, and parietal region in 2 patients. The CT angiography was performed on a 64-slice CT scanner. Thin-slice axial CT sections were acquired and a volume file was created of the arteriovenous malformation and the required skull bones. The file was then transferred to the 3D printer for creating the model. RESULTS: The model depicted the precise nature of the compactness and location of the nidus in relationship to the skull. It was possible to clearly delineate the course, size, and number of feeding vessels and draining veins. The model made identification of the normal and abnormal vessels easier and assisted in the preparation and conduct of surgery. The model was made to scale and was placed beside the surgeon during the operation. The limitation of current technology was that the exact differentiation of arteries and veins by color coding was not possible. CONCLUSION: 3D printed models can be helpful in getting information regarding the architecture and character of the arteriovenous malformation. The models are cost-effective and easy to build.

Orbital cortical approach to lesions around the frontal horn of the lateral ventricle: indication and surgical parameters.

BACKGROUND: An orbital cortical approach to lesions in the region of the frontal horn is described on the basis of surgical experience with five cases and dissections of three cadaveric brain specimens. The approach involves cortical incision over the orbital surface of the frontal brain and directing the surgical trajectory superiorly. The possible indications of the approach and the critical surgical parameters are described. METHOD: To assess the landmarks that could be used to employ the approach, three formalin-fixed frozen cadaveric brains were appropriately dissected. A number of parameters were analysed to identify the safe entry points and the trajectory to approach the frontal horn. Five lesions located in the region of the frontal horn were operated upon by employing the discussed approach. RESULTS: The frontal horn is located at the depth of approximately 18 mm (range, 17-20 mm) from the orbital surface of the frontal brain. In a lateral perspective, the tip of the frontal horn is in line with the tip of the temporal pole. Wide opening of the Sylvian fissure, relaxation of the brain and lateral basal frontal exposure can be used effectively to obtain a suitable angulation for conduct of surgery. Avoidance of olfactory tracts and Heubner's perforating artery at the site of medial orbital gyrus cortical incision and appropriately directing the corticectomy that avoids the association fibre tracts, caudate head and internal capsule can lead to a safe exposure of the frontal horn. The approach is suitable for lesions involving or in the vicinity of the inferior aspect of the frontal horn and in the region of the caudate head. Neuronavigation can be of assistance during surgery and avoid critical misdirection. All the five lesions were treated without consequence. CONCLUSIONS: For selected indications, an inferior frontal or orbital cortical approach can be used effectively and safely to approach lesions in relation to the frontal horn. The approach needs to be precise to avoid injury to vital adjoining structures.

3-D Printed Skull Model: Role in Identification of Site of Bone Defect in Cases with CSF Rhinorrhea.

Role of 3-D models in the identification of the site and extent of bone defects in the skull base for the treatment of CSF rhinorrhea is analyzed. Such models were used successfully in the management of two patients who failed previous attempts at basal reconstruction. The principal advantage of the models was in exact delineation of the size and site of bone defect and deciphering of its relationship with adjoining critical regions of the brain.

Anatomical analysis of white fiber tracts in SMA and its implications related to en-masse tumor resection technique.

OBJECTIVE: Anatomy and connections of the supplementary motor area (SMA) are studied essentially to analyze the SMA syndrome. Experience with surgical treatment of 19 tumors located in SMA is analyzed. MATERIAL AND METHODS: The cortical anatomy and subcortical connectivity of the SMA was studied on ten previously frozen and formalin fixed human cadaveric brain specimens. The white fiber dissection was performed using Klingler's method. Nineteen patients with low grade gliomas in the region of the SMA treated surgically were clinically analyzed. RESULTS: The white fiber connections of the SMA include short arcuate connections with the pre-central, middle and inferior frontal gyri, the medial part of the SLF, the cingulum, the frontal aslant tract (FAT), the claustro-cortical fibers, the fronto-striatal tract and the crossed frontal aslant tract. All tumors were operated using en-masse surgical technique described by us and its subsequent modifications that focused on attempts towards preservation of related critical fiber tracts namely FAT, cingulum and corpus callosum presumed to be responsible for postoperative SMA syndrome. Eight patients developed an SMA syndrome in the immediate post-operative period. Eleven patients did not develop any post-operative neurological deficits. In all these 11 patients it was apparent that the cingulum, FAT and the corpus callosal fibers were preserved during surgery by modifying the tumor resection technique. CONCLUSIONS: SMA syndrome is a frequent occurrence following surgery in patients with tumors in the region of the SMA complex. Surgical strategy that preserves the cingulum and the FAT can prevent the occurrence of the SMA syndrome.

Post-Traumatic Central or Axial Atlantoaxial Dislocation Presenting with "Atypical" Symptoms-Analyzing the Role of Dynamic Imaging on the Basis of Experience with 14 Patients Treated by Atlantoaxial Fixation surgery.

BACKGROUND: This is a report of a series of 14 patients who presented with a range of "atypical" cranial, spinal, and systemic symptoms that started after they suffered a relatively severe injury to the head and/or neck several months or years before surgical treatment. The implications of diagnosing and treating central or axial atlantoaxial dislocation (CAAD) is discussed. Also, the role of dynamic rotatory and lateral head tilt imaging in the diagnosis and treatment is analyzed. METHODS: Of the 14 patients, 7 were men and 7 were women, with an age range of 21-64 years (average, 42 years). Due to the severity of the presenting neurological and non-neurological symptoms, all the patients had lost their occupation and were heavily dependent on painkillers and/or antidepressant drugs. In addition to other characteristic clinical and radiological evidence, CAAD was diagnosed made based on the facet alignments on lateral profile imaging in the neutral head position. Dynamic head flexion-extension, lateral head tilt, and neck rotation imaging findings confirmed and subclassified CAAD. All 14 patients underwent atlantoaxial fixation surgery. RESULT: A personalized self-assessment clinical scoring parameter and the World Health Organization Disability Assessment Schedule 2.0 was used to evaluate the outcome. One patient did not follow-up after surgery. At a minimum follow-up of 6 months after atlantoaxial fixation surgery, the remaining 13 patients experienced relief from all major symptoms. CONCLUSIONS: Diagnosing and treating CAAD can have major therapeutic implications for patients presenting with progressively worsening disabling clinical symptoms following relatively severe head and/or neck trauma.

Defining role of atlantoaxial and subaxial spinal instability in the pathogenesis of cervical spinal degeneration: Experience with "only-fixation" without any decompression as treatment in 374 cases over 10 years.

Aim: The authors analyze their published work and update their experience with 374 cases of cervical radiculopathy and/or myelopathy related to spinal degeneration that includes ossification of the posterior longitudinal ligament (OPLL). The role of atlantoaxial and subaxial spinal instability as the nodal point of pathogenesis and focused target of surgical treatment is analyzed. Materials and Methods: During the period from June 2012 to November 2022, 374 patients presented with acute or chronic symptoms related to radiculopathy and/or myelopathy that were attributed to degenerative cervical spondylotic changes or due to OPLL. There were 339 males and 35 females, and their ages ranged from 39 to 77 years (average 62 years). All patients were treated for subaxial spinal stabilization by Camille's transarticular technique with the aim of arthrodesis of the treated segments. Atlantoaxial stabilization was done in 128 cases by adopting direct atlantoaxial fixation in 55 cases or a modified technique of indirect atlantoaxial fixation in 73 patients. Decompression by laminectomy, laminoplasty, corpectomy, discoidectomy, osteophyte resection, or manipulation of OPLL was not done in any case. Standard monitoring parameters, video recordings, and patient self-assessment scores formed the basis of clinical evaluation. Results: During the follow-up period that ranged from 3 to 125 months (average: 59 months), all patients had clinical improvement. Of 130 patients who had clinical evidences of severe myelopathy and were either wheelchair or bed bound, 116 patients walked aided (23 patients), or unaided (93 patients) at the last follow-up. One patient in the series was operated on 24 months after the first surgery by anterior cervical route for "adjacent segment" disc herniation. No other patient in the entire series needed any kind of repeat or additional surgery for persistent, recurrent, increased, or additional related symptoms. None of the screws at any level backed out or broke. There were no implant-related infections. Spontaneous regression of the size of osteophytes was observed in 259 patients where a postoperative imaging was possible after at least 12 months of surgery. Conclusions: Our successful experience with only spinal fixation without any kind of "decompression" identifies the defining role of "instability" in the pathogenesis of spinal degeneration and its related symptoms. OPLL appears to be a secondary manifestation of chronic or longstanding spinal instability.

Lumbar parafacetal cyst-spinal segmental instability is the cause and stabilization is the treatment: A clinical report of eight surgically-treated patients.

Objective: The authors report the results of "only-fixation" of the affected spinal segment without any decompression of the bones or soft tissue or manipulation of the cyst wall or contents in eight cases having lumbar parafacetal cyst (LPFC). This surgical strategy was based on the concept that LPFCs are secondary to spinal instability, has a protective or adaptive role, and is reversible following stabilization. Materials and Methods: During the period from January 2018 to January 2023, eight consecutive patients having LPFC were surgically treated. There were 5 males and 3 females, and their ages ranged from 48 to 72 years (average 63 years). Seven patients had a single cyst and one patient had multiple cysts. The patients presented with symptoms classically attributed to lumbar canal stenosis. Apart from the cyst-affected spinal segment, degenerative alterations were observed in adjoining spinal segments in six out of seven patients having a single cyst. All patients underwent "only fixation" of the unstable spinal segments without any kind of bone or soft-tissue resection and without any manipulation or handling of the cyst wall or contents. Results: During the follow-up period that ranged from 12 to 57 months (average 29 months), all patients improved from their symptoms. The recovery was observed in the immediate postoperative period and was lasting. Conclusions: LPFCs are one of the several secondary alterations observed in spinal degeneration. Identification of unstable spinal segments and their fixation constitutes rational treatment of lumbar parafacetal cysts. Direct handling and resection of cysts are unnecessary.