Adam Williams

The value of lumbar dorsal root ganglion blocks in predicting the response to decompressive surgery in patients with diagnostic doubt.

BACKGROUND CONTEXT Pain as a consequence of nerve root compression may not be easy to diagnose. Degenerative changes causing nerve root compression on magnetic resonance imaging (MRI) are common but not necessarily symptomatic while the distribution of pain attributable to a particular nerve root is variable. Selective dorsal root ganglion blocks (DRGBs) have been used in these situations to aid the diagnostic process, although their use remains controversial. PURPOSE We sought to investigate the positive predictive value of DRGBs in predicting response to decompressive surgery on a particular nerve root in a patient cohort with diagnostic uncertainty after clinical examination and MRI. STUDY DESIGN/SETTING This was a retrospective review of prospectively collected data on 100 consecutive patients. METHODS One hundred consecutive patients who underwent diagnostic DRGB under the senior author were identified retrospectively. Clinical records were reviewed for the reason for diagnostic uncertainty, level assessed, whether the DRGB reproduced pain typical for the patients symptoms, whether there was anatomically appropriate sensory and motor disturbance, whether good pain relief was achieved, and whether they had good response to surgery. RESULTS Of 100 patients recruited, four were removed from analysis owing to inadequate surgical decompression proven on postoperative MRI. Of the remaining 96 patients, 74 achieved immediate relief in their symptoms after DRGB. Fifty-one patients underwent surgical decompression after a successful root block; 41 patients achieved a good result from this surgery, and 10 did not. Nine patients who had no relief in their symptoms from DRGB still underwent surgery to decompress the same nerve root; six patients had relief of their symptoms from surgery, two did not respond, and one was lost to follow-up. The most common reason for diagnostic uncertainty was multilevel disease (74%) followed by patients with atypical pain (23%). The most common level assessed was the L5 nerve root. The positive predictive value was found to be 80.4%, the negative predictive value was 22.2%, with a sensitivity of 85.4% and a specificity of 16.7%. CONCLUSIONS In patients with diagnostic doubt, a positive DRGB is a good predictor of a positive outcome after surgery to decompress that nerve root. However, the negative predictive value is poor. This result could almost certainly be improved if there was a better definition of what constitutes a positive, and more importantly a negative, DRGB result. In the meantime, DRGBs are a useful adjunct in predicting the outcome of decompressive surgery in people with pain as a consequence of potential lumbosacral nerve root compression.

Radiological demonstration of spontaneous resolution of type 1 Chiari malformation in a 17-year-old patient

We describe a case report of 17-year-old gentleman in whom Chiari I malformation was seen on supine magnetic resonance imaging (MRI). Both previous and subsequent MRI studies showed normal position of the cerebellar tonsils. To our knowledge, this is the first example of the spontaneous appearance and resolution of a type 1 Chiari malformation on supine MRI without any identifiable cause.

Recognising contributions to work in research collaboratives: Guidelines for standardising reporting of authorship in collaborative research

BACKGROUND Trainee research collaboratives (TRCs) have been revolutionary changes to the delivery of high-quality, multicentre research. The aim of this study was to define common roles in the conduct of collaborative research, and map these to academic competencies as set out by General Medical Council (GMC) in the United Kingdom. This will support trainers and assessors when judging academic achievements of those involved in TRC projects, and supports trainees by providing guidance on how to fulfil their role in these studies. METHODS A modified Delphi process was followed. Electronic discussion with key stakeholders was undertaken to identify and describe common roles. These were refined and mapped to GMC educational domains and International Committee of Medical Journal Editors authorship (ICJME) guidelines. The resulting roles and descriptions were presented to a face-to-face consensus meeting for voting. The agreed roles were then presented back to the electronic discussion group for approval. RESULTS Electronic discussion generated six common roles. All of these were agreed in face-to-face meetings, where two further roles identified and described. All eight roles required skills that map to part of the academic requirements for surgical training in the UK. DISCUSSION This paper presents a standardised framework for reporting authorship in collaborative group authored research publications. Linkage of collaborator roles to the ICMJE guidelines and GMC academic competency guidelines will facilitate incorporation into relevant training curricular and journal publication policies.

Thoraco-lumbar spontaneous ligamentum flavum haematoma.

A 72-year-old female with a history of operated breast cancer, presented with a ten year history of episodic low back pain, an eight month period of typical lower limb neurogenic claudication and subjective sensory blunting in the left lower limb. Th ere was no history of trauma or urinary symptoms. On examination there was no spinal tenderness, neurologic defi cit in the lower limbs, nor root tension signs. MR imaging (Fig. 1)

Middle cranial fossa cystic schwannoma

The authors present the unusual case of a 37-year-old man, with a history of hepatitis C, presenting with a 3 year history of progressive trigeminal, facial and vestibular nerve defects. Intracranial imaging demonstrated a cystic middle and posterior fossa lesion, that was ultimately diagnosed as a cystic trigeminal schwannoma. Due to the uncertainties of diagnosis he was managed in two stages with an open biopsy and then a subsequent partial resection. Surveillance of the tumour remnant is planned. The rare nature of this diagnosis is discussed, along with the more common findings in intracranial schwannoma, and the wide differential to be considered. Briefly, the authors describe the surgical option for a complex multi-fossa schwannoma and the importance of the multi-disciplinary team in the diagnosis and management of such patients.