The ASSI monographs
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.232311
Source of Support: None, Conflict of Interest: None
The ASSI Monographs
Editors-in-chief : Gautam Zaveri, Raghava D. Mulukutla
Section editor : Gautam Zaveri
Pages : 108
ISBN : 978-93-86293-49-7
Lumbar spinal stenosis
Section editor : Amit C. Jhala
Pages : 177
ISBN : 978-93-86293-51-0
Complications in spine surgery
Section editor : Amol Rege
Vol. 1; Pages: 140
ISBN : 978-93-86293-53-4
Publisher : Thieme, Delhi
Year : 2018
General observations on the three volumes
These slim volumes are part of a series being published by the Association of Spine Surgeons of India (ASSI). The stated goal of this series is to provide updated information, decision-making algorithms and descriptions of surgical techniques on selected spinal problems. Whilst Indian authors dominate, the editors have obtained contributions from experts from abroad, whereever necessary.
Whilst chapters 1 and 2 deal with the diseases included under the umbrella of the term 'ankylosing spondylitis', their clinical features, diagnosis and medical treatment; the remaining seven chapters discuss surgical considerations – biomechanical aspects of spinal deformities, preoperative planning, anaesthetic considerations, peri- and post-operative care, specialized techniques in the treatment of cervical and thoraco-lumbar deformities, localised vertebral or discovertebral lesions of the spine, first described by Andersson in 1937, and finally, the management of spinal fractures in patients with ankylosing spondylitis.
The discussions on the evolution of the disease and immunological and histological observations during the development of the disease are brief but informative. The role of the human leucocytic antigen (HLA) class 1 and other molecules, and the current lacunae in understanding the complete pathogenesis is summarized well with references for further study. Figure 1.3 sums up the probable mechanisms by which populations of micro-organisms in the gut or skin (especially in patients with psoriasis) can combine with mechanical stress to spark off the series of events that eventually result in full-blown disease. The role of micro-organisms has been based on studies to detect antibodies against them in patients with ankylosing spondylitis and may be construed as a presumptive hypothesis. The exact triggers remain unidentified in most patients.
The chapter on medical treatment includes methods by which the outcome of treatment can be assessed. Boxes 2.1, 2.2 and 2.3 provide a summary of the tools commonly used. The discussion on tumor necrosis factor inhibitors and newer agents such as secukinumab and ustekinumab provides a guide on current trends in a rapidly changing field.
Care needed during radiological evaluation, electrophysiological monitoring during corrective surgery and restoration of the normal curvature in those with major deformities are dealt with under 'perioperative management'. The induction of general anaesthesia and the other care needed whilst the patient is unconscious during surgery is also discussed. Postoperative care and means for avoiding iatrogenic complications are also discussed here. The use of the word 'rehabilitation' in this section led me to expect description of short and long-term measures for helping the patient reach a normal or near-normal state but these are not mentioned.
The chapters on biomechanical aspects and preoperative planning provide useful guides on the management of spinal deformities, planning of corrective osteotomies and the extent of benefits that may follow. The information provided in them is supplemented in the chapters dealing specifically with deformities of the neck and trunk. Some complications during and after surgery are also considered in these chapters.
The final chapter on fractures of the spine in these patients highlights the inherent instability of the spine in such patients and emphasises the role of early operative stabilization to prevent neurological handicaps.
The comprehensive coverage of topics pertaining to this disease in this volume is enhanced by references to appropriate texts that can be consulted with profit. Whilst most chapters provide references up to 2016, some have the odd reference updated to 2017. This may be a consequence of the deadline that the authors had to meet. An index is provided.
Whilst this volume will be especially useful to spinal surgeons, there is much to benefit the neurosurgeon as well.
Lumbar spinal stenosis
The initial chapters discuss epidemiology; how stenosis develops; the abnormal findings noted on the study of stenotic spines; classification based on anatomic findings, cause of stenosis, complexity of stenosis and degree of compression of nerve roots. The findings on x-ray films and magnetic resonance (MR) imaging and the clinical manifestations of the disease are also demonstrated.
I failed to find a reference to stenosis of one half of the lumbar spinal canal. This entity was first described by Dr. P. E. Billimoria in Bombay in the days before computed tomography and MR scanning were being utilized for establishing neurological diagnoses. Using sagittal tomograms of high quality, he clearly demonstrated narrowing of just one half of the spinal canal in lumbar vertebrae, the stenosis being on the symptomatic side.
It is unfortunate that chapter one does not provide any Indian data on the incidence of stenosis. We need such statistics to help us understand the differences between what we see here as against what is described abroad. It also lacks illustrations of findings seen in the autopsy room or on histological slides. These would have conveyed the points the author wishes to make more effectively than do MR studies.
Residents in training in departments of neurology and neurosurgery will benefit from the descriptions and illustrations of clinical tests for stenosis and instability (chapter 3), details on balance in the sagittal plane and radiological measurements of spinal and pelvic tilts (chapter 2).
The cautionary note on selective nerve blocks for diagnostic purposes is well placed (page 32), as is the discussion on pain from associated degenerated knee joints in patients with spinal canal stenosis. Severe osteoarthritis of the knees may cause confusion as to whether spine or knee must be given priority during treatment (page 34).
Chapters 4 – 14 deal with therapy. Non-operative therapy, conventional decompression of nerve roots, 'minimally invasive' and endoscopic decompression, 'minimally invasive decompression and fusion' are dealt with here.
The references provided on the efficacy of epidural corticosteroid injections are from western journals and texts. We need evaluations by Indian authors of methods in use here and how well they work in the short and medium term. This has become increasingly important as 'Spine clinics' proliferate and advertise freely in the media, their 'successes' in obviating surgery.
Operative techniques are described in detail. The illustrations showing key steps are clear and well designed. Prevention of such complications as operating at the wrong level, inadequate decompression, troublesome bleeding from engorged veins and dural tear is highlighted.
The ultrasonic bone cutter has been described briefly, which works on a principle similar to that of the instrument used to pulverize and aspirate soft-tissue tumours.
A separate chapter discusses indications and techniques for spinal fusion in patients with stenosis. Tables 6.1, 6.2 and 6.3 provide checklists for criteria that help to diagnose instability. The difficulties that the patient faces following iatrogenic, post-operative instability are discussed briefly. A cautionary note is provided on attempting fusion in the elderly with markedly osteoporotic spines and movement disorders such as Parkinson's disease. The points on complications and limitations of the various techniques used in spinal fusion will benefit young readers (pages 70-72).
Equally significant are chapters 7 and 14 where outcomes of surgery for lumbar canal stenosis are discussed. These should be made required reading for all surgeons in training for operations on the spine.
Eleven case studies are presented in the final chapter. It would have helped the reader if a two-line summary of the lessons learnt from each of these patients would have been provided.
Complications in spine surgery. Volume 1
This volume describes complications following operations on the cervical, dorsal and lumbar spine.
Dural tears; bleeding during surgery and damage to blood vessels; dysphagia, dysphonia and esophageal injury during and after surgery on the cervical spine through the anterior approach; infection; complications related to screws inserted into pedicles; damage to nerves; kyphosis and pseudarthrosis are dealt with here. Chapter 7 deals with persistence or recurrence of symptoms despite surgery.
The chapter on dural tears refers to the increased risk of cerebrospinal fluid (CSF) leak when the patient is known to have a connective tissue disorder. This emphasizes the need for greater care when operating on patients with such abnormalities as Ehlers-Danlos or Marfan's syndromes in whom the dural tube may be fragile. An important tip, not mentioned in this chapter, is to look out for thin strands of fibrous tissue connecting the dura to the ligamentum flavum. A tug on the ligament without dividing such strands has led to dural tears. The chapter has excellent illustrations clearly demonstrating the difference between serous ooze and CSF leak through the wound, the hernia of arachnoid through a dural tear. Another tip, not mentioned in this chapter, is to lower the head end of the operation table during repair of the tear so as to reduce the quantity of CSF emerging from the tear. The controversy regarding the use of a subfascial drain is well highlighted.
Table 2.1 sums up the various factors that may contribute to excessive bleeding during spinal surgery. Figure 2.1a and b show how pressure on the abdomen can be avoided when the patient is prone. (Figure 5.3 in the volume dealing with lumbar canal stenosis shows the Relton-Hall frame that can be useful for this purpose.) This chapter also deals with injury to the carotid and vertebral arteries during operations on the neck; and, injuries to the aorta, iliac arteries and inferior vena cava when operating on the thoracic and lumbar spine. Diagrams explaining how such injuries can occur are well chosen and the algorithm describing the relevant steps once injury to the vertebral artery has been detected is comprehensive. The cautionary note against relying on tamponade in such injuries is noteworthy.
Chapter 3, dealing with complications after surgery on the cervical spine when the spine is approached via the anterior route, is in two parts. Injury to the pharynx and upper oesophagus is discussed first. The patient with perforation of the pharynx three years after the insertion of cage, plate and screws demonstrates the need for prolonged follow-up evaluation. The second half deals with dysphonia. The key points sum up what is described in detail in the text.
Infection at the site of surgery is always a dreaded complication, especially when metallic or bony implants have been used. Chapter 4 outlines the preventive measures and the management of established infection. The authors prefer the use of vancomycin power in the wound as one of the means for preventing the growth of micro-organisms. Steps to be taken after infection has been diagnosed are summarized in the algorithm shown in Figure 4.3. The authors prefer to retain a stable implant, removing it only if it is loose. Four illustrative case studies are provided.
Chapter 5 describes complications related to insertion of screws into pedicles. Figure 5.1 shows the architecture of the pedicle and the following table lists the pedicle width at each level in the thoracic and lumbar spine. Table 5.2 lists the distance of the dural tube from the inner surface of the pedicle between D11 and L5. The proximity of the nerve roots to the inferior surface of the lumbar pedicles is emphasized. Discussion of the diagnosis and treatment of malpositioned screws is followed by means by which this complication can be avoided. Facet joint injury, loosening and breakage of the screw over time, injuries to blood vessels and viscera, complications after percutaneous pedicle screw fixation and the use of screws in juveniles are also discussed.
The chapter on neurological complications in spinal surgery points out that 'meticulous, if not obsessive care must be taken at each step of surgery' to prevent these mishaps from occurring. Since such complications may prove irreversible, this statement deserves emphasis. The use of neurophysiological monitoring, care in positioning of patients with an unstable spine and during the induction of general anaesthesia, gentle handling especially when using the monopolar cautery and the Cobb's elevator, being well-acquainted with the use of a microscope, and care during the instrumentation procedure are some of the preventive measures referred to. The cautionary note on the use of high-speed drills, sharp osteotomes and large rongeurs is well placed. Steps to be taken when nerve injury has been detected are summarized in Table 6.3.
I applaud the advice to provide the patient and family full information on what went wrong, the measures being adopted to restore normalcy and the probable prognosis. It has been repeatedly shown that honesty and sincerity go a long way in averting unpleasant and time-consuming lawsuits.
Persistent or recurrent leg pain after surgery on the lumbar spine is dealt with in chapter 7. Table 7.1 sums up the likely causes. The vexatious issues of localized epidural scarring and arachnoiditis are discussed along with other causes of such pain. Extensive epidural fibrosis has also been referred to as 'formation of a post-laminectomy membrane' in journals and books.
Whilst arachnoiditis was more frequent in the days when myelography was the investigation of choice, it continues to pose a problem even when iophendylate is no more used in the era of MR scanning. The fact that treatment ranges from the use of analgesics to behavioural therapy underlines the difficulty in rendering the affected patient asymptomatic.
The final chapters deal with proximal junctional kyphosis (a consequence of the dominance of technology over surgical judgment) and lumbar spinal pseudarthrosis as a consequence of failure of fusion. In the latter event, the authors emphasise the importance of prevention.
Some observations on the layout and presentation of each volume
I was sorry to see an almost total absence of any details on the history of spinal surgery in India and abroad. A notable exception has been the section editor of the volume on lumbar canal stenosis, who has traced in two paragraphs some salient historical facts.
Likewise, there is no reference to the ethical aspects of operations on the spine. The inclusion of these two topics would have provided perspectives that would have enhanced the understanding of younger readers and benefitted their patients.
Each chapter has well-defined sections, clear diagrams, tables, charts and photographs.
The authors appear to have been permitted some latitude in designing their essays. Some chapters carry a section just preceding the references, listing the key points discussed. Some clinical chapters also carry sections such as Pearls and Pitfalls.
As expected of Thieme, each volume is a visual delight.