Painful rib hump: a new clinical sign for detecting intraspinal rib displacement in scoliosis due to neurofibromatosis

Myelopathy Associated with Rapid Progression of a Dystrophic Neurofibromatosis-1 Curve - A Case Report and Review of Literature

Introduction

Thoracic myelopathy in neuro fibromatosis-1 (NF-1) is most commonly due to intra-spinal neurofibromas/dumb-bell tumors/intra-canal rib head penetration (RHP) causing cord compression. However, acute thoracic myelopathy due to rapid progression of the kyphoscoliotic curve alone in NF-1 without a significant spinal cord compression occurs very rarely. This case report discusses our experience with one such patient and we also discuss intraoperative and post-operative challenges encountered with this patient and a rare complication of hemothorax postoperatively.

Case Report

A 15-year-old male presented to the clinic after being lost to follow-up for 4 years with a rapid acute deterioration of dystrophic curve and no myelopathic symptoms (Scoliosis - 65°, Kyphosis - 77°). His subsequent examination in 6 weeks showed acute development of myelopathic gait with right ankle and extensor hallucis longus weakness. He was admitted for halo gravity traction for 6 weeks and a single-stage posterior instrumentation with excision of rib heads at the apex was planned. Postoperatively, the patient developed massive left hemothorax and loss of power in both lower limbs at day 2. He subsequently regained full power and complete resolution of myelopathic symptoms at the end of 9- month follow-up with a satisfactory alignment of spine in the follow-up X-rays.

Conclusion

Acute onset of myelopathy is a rare and uncommon finding with a rapid deterioration of dystrophic curve alone without any major spinal cord compromise. Early detection of dysplastic changes with early aggressive surgical management and deformity correction is necessary with dystrophic NF-1 curves to prevent pre-operative and post-operative morbidities.

Is scoliosis a source of pain?

Purpose

Pain in scoliosis is definitely a hot topic with growing popularity. The literature remains very controversial, with a pain prevalence ranging from 23% to 90%, but this can be explained by the great heterogeneity of the numerous series. The aim of this review was to report results from the literature regarding pain in relation to scoliosis regardless of the etiology.

Methods

A bibliographic search in Medline and Google database from 2003 to March 2023 was performed. Relevant literature was analyzed, summarized, and discussed based on authors' experience. A 1-year prospective series of adolescent idiopathic scoliosis patients was also included to compare with the existing literature.

Results

A total of 126 adolescent idiopathic scoliosis patients were included, with a mean preoperative Cobb angle of 64.5° (range, 45°-112°). Reported pain prevalence was 34.1%. Pain and no-pain groups were very different in their self-reported experience, with a very low mean visual analogue scale score of 0.5 (± 0.6) in the no pain group, while visual analogue scale averaged 5.6 (± 1.2) in the pain group (p < 0.001). No significant difference was found between groups regarding the most relevant demographic and radiological parameters.

Conclusion

Evidence-based literature on "scoliosis as a source of pain" remains ambiguous. There seems to be a consensus on the lack of direct relationship between deformity magnitude and back pain intensity. A comprehensive evaluation of the patient is therefore necessary before any treatment, including medical history, clinical examination, and relevant imaging for any child with scoliosis and back pain.

Level of evidence

Level VI.

Could screw/hook insertion at the apical vertebrae with rib head dislocation effectively retract the corresponding rib head from spinal canal in dystrophic scoliosis secondary to type 1 neurofibromatosis?

Background

Rib head dislocation (RHD) in dystrophic scoliosis of type 1 neurofibromatosis (DS-NF1) is a unique disorder caused by skeletal dystrophy and scoliotic instability. No particular surgical manipulation is mentioned in the literature to instruct the spine surgeons to effectively obtain more migration of the dislocated rib head without resection. The present study aimed to investigate the effectiveness of screw/hook insertion at vertebrae with RHDs on the retraction of penetrated rib head from spinal canal.

Methods

37 neurologically intact patients with DS-NF1 and concomitant 53 RHDs undergoing scoliosis surgery without rib head excision were retrospectively reviewed. We used pre and postoperative whole-spine radiographs to determine the Cobb angle and the vertebral translation (VT), and the CT scans to evaluate the intraspinal rib length (IRL) and rib-vertebral angle (RVA). The dislocated ribs were assigned into two groups according to the presence of screw/hook insertion at vertebrae with RHD: screw/hook group and non-screw/hook group.

Results

37 dislocated ribs with screws/hooks insertion at corresponding vertebrae were assigned into the screw/hook group and the remaining 16 dislocated ribs consisted of the non-screw/hook group. In the screw/hook group, the correction rates of Cobb angle and VT were significantly higher than the non-screw/hook group after surgery (58.7 ± 16.0% vs. 30.9 ± 12.4%, p = 0.003; 61.8 ± 18.8% vs. 35.1 ± 16.6%, p = 0.001; respectively). Similarly, more correction rates of IRL and RVA were found in the screw/hook group than the non-screw/hook group (63.1 ± 31.3% vs. 30.1 ± 20.7%, p = 0.008; 17.6 ± 9.7% vs. 7.2 ± 3.6%, p = 0.006; respectively). Multiple linear regression analysis revealed that the correction rates of Cobb angle, VT and RVA contributed significantly to correction of IRL (β = 0.389, 0.939 and 1.869, respectively; p = 0.019, 0.001 and 0.002, respectively).

Conclusion

Screw/hook insertion at dystrophic vertebrae with RHDs contributed significantly to the degree of retraction of penetrated rib head from spinal canal. This effectiveness is mediated by more corrections of VT and RVA.

Management of NF-1 dystrophic scoliosis associated with rib heads dislocation into the spinal canal in neurological intact patients: a systematic literature review

PURPOSE

The management of scoliosis and kyphoscoliosis in patients with Type 1 Neurofibromatosis (NF-1) among spinal surgeons is still challenging due to the severity of the deformity especially in dystrophic deformity types. This rapid and progressive condition is likely to be associated with dislocated rib heads into the spinal canal, hence representing a real dilemma on the decision making between its resection versus not resection during the corrective surgery, especially in patients with normal neurological status. The objective of this publication is to discuss the management options in this patient population through a literature review.

METHODS

A comprehensive systematic literature search was performed for relevant studies using PubMed, Web of Science, and Scopus databases. Previous publications depicting neurologically intact patients with NF-1 and rib dislocation into the canal were reviewed. Articles reporting individual cases or case series/cohorts with patient-discriminated findings were included.

RESULTS

The data collection retrieved a total of 55 neurologically intact patients with NF-1 dystrophic scoliosis and rib penetration into the canal who underwent spinal surgery. Among them, 37 patients underwent surgery without head rib resection and 18 patients with rib excision. No patient presented postoperative neurological deficit except for one case of late postoperative neurological deterioration reported in a patient within situ fusion in which the surgeons ignored the presence of previous spinal cord compression.

CONCLUSION

Corrective surgery for patients with NF-1 and rib penetration into the canal in neurologically intact patients can be safely performed without the resection of the dislocated rib heads without a higher risk of neurological compromise.

Surgical treatment of post-traumatic luxation of rib heads with spinal cord compression in a cat

BACKGROUND

Luxation of the rib head with intrusion into the intervertebral foramen seems to be rare in cats. Only one report has been published describing a cat with non-ambulatory paraparesis, which was managed conservatively. Here we report a case of rib head luxation that was managed surgically.

CASE PRESENTATION

A 4-year-old, female domestic shorthair cat with a two-week history of non-ambulatory paraparesis was presented at our clinic. Based on history and neurological examination, a diagnosis of thoracolumbar spinal cord lesion of traumatic origin was made. Computed tomography scanning revealed mild scoliosis, a luxation of the 3rd and 4th right rib heads and penetration into the spinal canal through intervertbral foramina. Surgical management using right dorsal approach to the spine was performed. The spinal cord was decompressed by cutting and removing of proximal ribs' fragments by rotation and pulling out from the intervertebral foramina. The cat was ambulatory and paraparetic four weeks after surgery. Two years after surgery the cat regained functional gait, but ataxia remained.

CONCLUSIONS

We report the first case of a surgical treatment of rib head luxation and intrusion into the spinal canal in a cat. The applied procedure resulted in an improvement of neurological signs.

The Haleem-Marks-Botchu classification: a novel CT-based classification for intracanal rib head penetration

PURPOSE

Intracanal rib head penetration is a well-known entity in dystrophic scoliotic curves in neurofibromatosis type 1. There is potential for spinal cord injury if this is not recognised and managed appropriately. No current CT-based classification system is currently in use to quantify rib head penetration. This article aims to propose and evaluate a novel CT-based classification for rib head penetration primarily for neurofibromatosis but which can also be utilised in other conditions of rib head penetration.

MATERIALS AND METHODS

The grading was developed as four grades: normal rib head (RH) position-Grade 0, subluxed extracanal RH position-Grade 1, RH at pedicle-Grade 2, intracanal RH-Grade 3. Grade 3 was further classified depending on the head position in the canal divided into thirds. Rib head penetration into proximal third (from ipsilateral side)-Grade 3A, into the middle third-Grade 3B and into the distal third-Grade 3C. Seventy-five axial CT images of Neurofibromatosis Type 1 patients in the paediatric age group were reviewed by a radiologist and a spinal surgeon independently to assess interobserver and intraobserver agreement of the novel CT classification. Agreement analysis was performed using the weighted Kappa statistic.

RESULTS

There was substantial interobserver correlation with mean Kappa score (k = 0.8, 95% CI 0.7-0.9) and near perfect intraobserver Kappa of 1.0 (95% CI 0.9-1.0) and 0.9 (95% CI 0.9-1.0) for the two readers.

CONCLUSION

The novel CT-based classification quantifies rib head penetration which aids in management planning.

Does spinal deformity correction of non-dystrophic scoliosis in neurofibromatosis type I with one-stage posterior pedicle screw technique produce outcomes similar to adolescent idiopathic scoliosis?

BACKGROUND CONTEXT

The efficacy of one-stage posterior pedicle screw instrument used in the treatment of non-dystrophic scoliosis in neurofibromatosis type I (NF-1) is unknown. Also, there is no study that has directly compared the results of spinal deformity correction between non-dystrophic scoliosis in NF-1 and adolescent idiopathic scoliosis (AIS).

PURPOSE

The objectives of this study were to study the efficacy of a one-stage posterior pedicle screw instrument used in the treatment of non-dystrophic scoliosis in NF-1 and to compare non-dystrophic scoliosis in NF-1 with matched AIS to illustrate the differences.

STUDY DESIGN

This is a retrospective case control study.

PATIENT SAMPLE

Fifteen patients with non-dystrophic scoliosis in NF-1 and 15 patients with AIS underwent a one-stage posterior surgery with the pedicle screw system.

OUTCOME MEASURES

Preoperative and postoperative whole-spine radiographs were used to determine coronal and sagittal Cobb angles. Also, the distance between the C7 plumb line and the center sacral vertical line and the sagittal vertebral axis was measured to assess spinal balance. The Scoliosis Research Society (SRS)-22 questionnaire was used to evaluate functional outcomes.

METHODS

We matched 15 patients with non-dystrophic scoliosis in NF-1 with patients with AIS (ratio, 1:1) for age, sex, and degree of major deformity. The overall mean age was 13.4±2.0 and 14.0±2.1 years, respectively. The NF-1 group consisted of 10 boys and 5 girls, and the AIS group consisted of 9 boys and 6 girls. The mean follow-up was 37.6±3.9 and 33.5±5.0 months, respectively. The AIS group underwent end vertebra (EV) or EV+1 fusion. The NF-1 group underwent EV+1, 2, or 3 fusion. Both coronal and sagittal Cobb angles, trunk balance, operative time, blood loss, fusion levels, length of stay, and scores on the SRS-22 questionnaire were compared between the two groups. The study was supported by the National Natural Science Foundation of China (Grant No. 81401760). There were no study-specific conflict of interest-associated biases.

RESULTS

The preoperative main curve magnitude was similar between the two groups; however, the flexibility of the NF-1 group tended to be less than that of the AIS group. The rate of correction of the main curve obtained surgically (79.8% compared with 81.1%) was similar in the NF-1 and AIS groups. There were no significant differences in the loss of correction between the two groups (p>.05). Also, there were no significant differences between the groups in operative time, blood loss, fusion levels, screw number, length of stay, trunk balance, and scores on the SRS-22. There were no serious complications related to surgery in both groups.

CONCLUSIONS

Despite the differences in preoperative flexibilities and fusion strategies, non-dystrophic scoliosis in NF-1 can be treated with a satisfied correction rate and progression rate similar to comparable AIS by using the one-stage posterior pedicle screw technique. Dural ectasia or thin pedicles in non-dystrophic scoliosis could make pedicle screw placement challenging.

Posterior Correction Without Rib-head Resection for Patients With Neurofibromatosis Type 1, Dystrophic Scoliosis, and Rib-head Protrusion Into the Spinal Canal

STUDY DESIGN

A retrospective study.

OBJECTIVE

The objective of this study is to report the result of patients with neurofibromatosis type 1(NF-1), dystrophic scoliosis, and rib-head protrusion into the spinal canal who received posterior scoliosis correction surgery without rib-head resection.

SUMMARY OF BACKGROUND DATA

A total of 124 patients with NF-1 and dystrophic scoliosis were treated at our institution during the study period. Eight patients with a median age of 12 years had rib-head protrusion into the spinal canal and received surgery and were included in the analysis.

METHODS

All 8 patients (6 male, 2 female) were treated from 2003 to 2013 and received posterior correction with a pedicle screw-rod 3-dimensional correction system or screw-hook hybrid system. Scoliosis correction rate and percentage of spinal canal occupied by the rib head were analyzed.

RESULTS

The median patient age, number of segments fused, and follow-up duration were 12 years, 10.5, and 22.5 months, respectively. There were no surgery-related complications, and symptoms in all patients improved after surgery. The median postoperative and 1-year follow-up sagittal kyphotic angles were significantly smaller as compared with the preoperative value (28.5 and 31 vs. 62.5 degrees, P=0.012). The median postoperative coronal Cobb angle of the main thoracic curve was significantly smaller compared with the preoperative value (29 vs. 64.5 degrees, P=0.012). The median percentage of the spinal canal occupied by the intraspinal rib was significantly lower at 1-year follow-up compared with the preoperative value (23.1% vs. 28.6%, P=0.018).

CONCLUSIONS

Posterior correction without rib-head excision can provide good outcomes for patients with NF-1 and dystrophic scoliosis and rib-head protrusion into the spinal canal.

Thoracic compression myelopathy due to the progression of dystrophic scoliosis, the presence of a paraspinal tumor, and high and excessive amplitude movement of the shoulder

The authors present a case of 45-year-old man with neurofibromatosis type 1 (NF-1) and thoracic scoliosis, previously undergoing fusion surgery, who developed myelopathy. This patient further complained of lightning pain when he extended and horizontally abducted the convex-side shoulder. Radiological examination revealed the progression of dystrophic scoliosis with opened spinal canals and the presence of a neurofibroma behind the spinal cord at the apical levels. Delayed development of spinal instability can occur due to dystrophy even postoperatively in patients with NF-1. After tumor resection, he had rapid recovery from myelopathy and no recurrence of radiating pain despite shoulder movement. These findings provide a speculation that high, intense amplitude movement of the shoulder toward the spinal canal causes the impingement on the neurofibroma, resulting in indirect compression of the exposed spinal cord. This is the first report describing thoracic compression myelopathy associated with paraspinal displacement of the scapula.

Surgical Management of Intracanal Rib Head Dislocation in Neurofibromatosis Type 1 Dystrophic Kyphoscoliosis: Report of Two Cases and Literature Review

There is still no consensus on the management of severe intracanal RH dislocation in neurofibromatosis type 1 dystrophic kyphoscoliosis. This study notes the early cord function impairment signs, reports a serious complication in a susceptible cord, identifies possible mechanisms of injury, and discusses the management of intracanal RH dislocation presented in the literature. First report is as follows: a 12-year-old female with cord compromise and preoperative neurology that underwent thoracotomy and anterior release. The RH was left in situ following a rib excision. During the posterior stage of the procedure she presented with complete loss of all IOM traces prior to any correction manoeuvres. The neurology recovered 72 h postop and the final correction and instrumented fusion were uneventfully completed 15 days postop. Second report is as follows: a 10-year-old male, whose only neurology was a provoked shock-like sensation to the lower limbs following direct pressure on the rib cage. He underwent an uneventful posterior RH excision and instrumented correction and posterior spinal fusion. In conclusion, any possible cord dysfunction sign should be sought during examination. Decompression of the spinal cord by resecting the impinging bony part, even in the absence of neurological symptoms, is advised before any attempt to release or correct the deformity.

Posterior-only spinal fusion without rib head resection for treating type I neurofibromatosis with intra-canal rib head dislocation

OBJECTIVES

Patients with Type I neurofibromatosis scoliosis with intra-canal rib head protrusion are extremely rare. Current knowledge regarding the diagnosis and treatment for this situation are insufficient. The purpose of this study is to share our experience in the diagnosis and surgical treatments for such unique deformities.

METHODS

Six patients with Type I neurofibromatosis scoliosis with rib head dislocation into the spinal canal were diagnosed at our institution. Posterior instrumentation and spinal fusion without intra-canal rib head resection via a posterior-only approach was performed for deformity correction and rib head extraction. The efficacy and outcomes of the surgery were evaluated by measurements before, immediately and 24 months after the surgery using the following parameters: coronal spinal Cobb angle, apex rotation and kyphosis of the spine and the intra-canal rib head position. Post-operative complications, surgery time and blood loss were also evaluated.

RESULTS

Patients were followed up for at least 24 months post-operatively. The three dimensional spinal deformity was significantly improved and the intra-canal rib head was significantly extracted from the canal immediately after the surgery. At follow-up 24 months after surgery, solid fusions were achieved along the fusion segments, and the deformity corrections and rib head positions were well maintained. There were no surgery-related complications any time after the surgery.

CONCLUSIONS

Systematic examinations are needed to identify patients with Type I neurofibromatosis scoliosis with rib head dislocation into the canal who can be treated by posterior-only spinal fusion without rib head resection.

Double rib penetration of the spinal canal in a patient with neurofibromatosis

BACKGROUND

Rib head penetration into the spinal canal in patients with severe kyphoscoliosis secondary to neurofibromatosis type-1 (NF-1) is extremely rare. Double rib head penetration has only been reported once earlier.

METHODS

We are reporting on an adolescent male with NF-1 and severe thoracic kyphoscoliosis with adjacent double rib head penetration into the spinal canal without neurological deficits. Only one was recognized on the initial radiographic imaging.

RESULTS

A 14-year-old with NF-1 and 74 degrees left thoracic scoliosis and 75 degrees kyphosis was treated at our institution. Preoperative computed tomography (CT) demonstrated protrusion of the left T6 rib head into the spinal canal on the convexity of the curve, compressing the spinal cord. Staged surgical procedures for resection of the rib head and correction of the spinal deformity were planned. After presumed successful resection of the penetrated rib head, a postoperative CT revealed the presence of a second adjacent left T7 rib head in the spinal canal. This was not initially recognized owing to the severe deformity and image obliquity of the CT gantry. Another procedure was performed to remove this rib head. He was then placed in halo traction until anterior and posterior spinal fusion and segmental spinal instrumentation were performed. He achieved good deformity correction and had no neurological deficits throughout his treatment.

CONCLUSIONS

Rib head protrusion into the spinal canal can occur with spine deformity in NF-1. If present, the imaging should be carefully reviewed for the possibility of an adjacent rib head penetration that may have been obscured by the limitations of CT in the context of a dysplastic spinal deformity.

LEVEL OF EVIDENCE

Level V. Case study.

Post-traumatic thoracic scoliosis with rib head dislocation and intrusion into the spinal canal: a case report and review of literature

The objective of the study was to report a rare occurrence of dislocation and intrusion of two rib heads into the spinal canal at the convex apex of a post-traumatic thoracic scoliosis in an adult in the absence of any neurological impairment. A 47-year-old male presented with a slowly progressive, post-traumatic thoracic scoliosis and a mild aching sensation over the posterior chest wall. The lower limb neurology and bowel and bladder function were normal. There was no clinical evidence of neurofibromatosis. CT scans showed that the 8th and 9th ribs on the convex apex of the scoliotic curve had intruded into the spinal canal and were lying adjacent to the dura and spinal cord. The MRI scan did not show any cord signal intensity changes. Although rib dislocation and intrusion into the spinal canal is uncommon, images should be carefully analysed to rule out this condition in sharp angular scoliotic curves.

Rib head protrusion into the central canal in type 1 neurofibromatosis

BACKGROUND

Intraspinal rib head dislocation is an important but under-recognized consequence of dystrophic scoliosis in patients with neurofibromatosis 1 (NF1).

OBJECTIVE

To present clinical and imaging findings of intraspinal rib head dislocation in NF1.

MATERIALS AND METHODS

We retrospectively reviewed clinical presentation, imaging, operative reports and post-operative courses in four NF1 patients with intraspinal rib head dislocation and dystrophic scoliosis. We also reviewed 17 cases from the English literature.

RESULTS

In each of our four cases of intraspinal rib head dislocation, a single rib head was dislocated on the convex apex of the curve, most often in the mid- to lower thoracic region. Cord compression occurred in half of these patients. Analysis of the literature yielded similar findings. Only three cases in the literature demonstrates the MRI appearance of this entity; most employ CT. All of our cases include both MRI and CT; we review the subtle findings on MRI.

CONCLUSION

Although intraspinal rib head dislocation is readily apparent on CT, sometimes MRI is the only cross-sectional imaging performed. It is essential that radiologists become familiar with this entity, as subtle findings have significant implications for surgical management.

Costovertebral fracture dislocations: important radiographically difficult diagnosis

The authors' aim is to report the appearance of fracture dislocations of the costovertebral joint. We will review the pertinent anatomy of the costovertebral articulation, summarize the current literature, report our experience and the imaging appearance of costovertebral joint fracture dislocations, and discuss important concepts of the costovertebral joint, as it relates to thoracic spine fractures.

Impingement of spinal cord by dislocated rib in dystrophic scoliosis secondary to neurofibromatosis type 1: radiological signs and management strategies

STUDY DESIGN

Case series.

OBJECTIVE

To define radiologic diagnosis and treatment strategies of rib dislocation to prevent serious complications during deformity surgery.

SUMMARY OF BACKGROUND DATA

Rib dislocation into the spinal canal caused by the dystrophic changes seen in scoliotic patients with neurofibromatosis type 1 (NF-1) may cause severe complications when neglected. The risk of this complication is increased by modern instrumentation techniques that produce greater correction.

METHODS

Three neurologically intact neurofibromatosis patients with scoliosis on whom rib dislocations were determined on convex side of the apical vertebrae were evaluated.

RESULTS

Three cases were operated with modern instrumentation and correction techniques either with anterior and posterior approaches with or without rib head excisions, to prevent cord injury. There were no neurologic complications postoperatively.

CONCLUSION

Apical convex rib head dislocation into the canal in NF-1 scoliotic patients can be suspected by conventional radiograms and be proven by CT and MRI. The rib dislocation is not a contraindication to deformity correction with modern spinal instrumentation techniques when preventive measures are applied.

Scoliosis associated with neurofibromatosis

Neurofibromatosis type 1 (NF-1) is a multisystemic disease. It may manifest as abnormalities of the nervous tissue, bones, soft tissue, and skin. The manifestations of NF-1 vary from person to person and range from subclinical to severe. Individuals who carry the gene eventually exhibit some clinical feature of the disease. The penetrance for NF-1 nears 100% during adulthood. Skeletal abnormalities are common in NF-1, with most patients presenting with some type of bony dysplasia. The orthopedic complications usually appear early. They include spinal deformities, such as scoliosis or kyphosis, congenital tibial dysplasia with bowing and pseudarthrosis of the tibia, forearm, other bones, as well as overgrowth phenomenon of an extremity, and soft tissue tumors.